Game plan
John Isner v Felix Auger Aliassime
Every number combines what John Isner does well with what Felix Auger Aliassime allows, each measured against the tour average and shrunk toward it when the sample is thin. Flip perspective
Forecast
Each player's serve and return strength is fitted against every opponent they were charted against, so a record built on weak opponents counts for less. At least one of them is no longer active or has too little charted in the last three seasons, so both are compared on their careers. The result is then nudged by John Isner's record against Felix Auger Aliassime's tactical lookalikes and in their charted head-to-heads (lookalikes: −3.6 on serve, −7.0 on return vs expectation (401 points); head-to-head: −1.6 on serve, +9.0 on return vs expectation (159 points)). A game-by-game Markov chain turns point odds into match odds; the 90% range covers the uncertainty in the two strengths, not the nudges. Charted matches lean toward big events, so treat this as a scouting estimate, not a betting line.
Head to head, per 100 shots
| Career | John | Felix |
|---|---|---|
| Direction choice | −0.13 ±0.05 better than 25% | +0.01 ±0.05 better than 60% |
| Shot selection | +0.62 ±0.09 better than 96% | +0.50 ±0.08 better than 93% |
| Execution | −0.90 ±0.33 better than 28% | −0.79 ±0.31 better than 33% |
| Points left on the table | 2.98 ±0.11 lower than 20% | 2.50 ±0.09 lower than 60% |
Each player's career against an average tour player in the same position, adjusted for opponent strength, with a 90% margin (shots clustered by match). Points left on the table is the gap to the best-value direction for the same stroke, so lower is better. Percentiles are within each player's own tour. A side is highlighted only when the gap is larger than the margin on the difference.
Serve plan
The share of points the server wins when a first serve lands in that direction (hover a rate for its 90% interval; ± is the 90% margin). "Matchup" combines the server's rate with how this returner handles that serve. "Optimal" is the mix that wins most against this returner once they start reading a habit, at the response measured across the tour, and only within the range servers' habits actually vary. The gain over the current mix is how exploitable that mix is.
John Isner serving
Deuce court
| 1st serve | Now | John wins | v Felix | Matchup | Optimal |
|---|---|---|---|---|---|
| Wide | 52% | 78% | 75% | 80.4%±2.3 | 65% ▲ |
| Body | 9% | 61% | 64% | 61.7%±6.3 | 0% ▼ |
| T | 39% | 78% | 74% | 77.0%±2.8 | 35% ▼ |
Optimal v Felix Auger Aliassime: +1.2±0.5 per 100 first serves (faults included) over the current mix. Serving wide every time would read +3.0 per 100 first serves in before the returner adjusts.
Ad court
| 1st serve | Now | John wins | v Felix | Matchup | Optimal |
|---|---|---|---|---|---|
| Wide | 47% | 80% | 72% | 79.1%±2.6 | 44% ▼ |
| Body | 6% | 66% | 65% | 68.3%±7.2 | 0% ▼ |
| T | 47% | 79% | 74% | 80.2%±2.6 | 56% ▲ |
Optimal v Felix Auger Aliassime: +0.5±0.4 per 100 first serves (faults included) over the current mix. Serving T every time would read +1.2 per 100 first serves in before the returner adjusts.
Felix Auger Aliassime serving
Deuce court
| 1st serve | Now | Felix wins | v John | Matchup | Optimal |
|---|---|---|---|---|---|
| Wide | 50% | 78% | 79% | 82.6%±2.3 | 45% ▼ |
| Body | 8% | 66% | 76% | 77.8%±4.9 | 0% ▼ |
| T | 42% | 78% | 84% | 86.3%±2.0 | 55% ▲ |
Optimal v John Isner: +0.7±0.4 per 100 first serves (faults included) over the current mix. Serving T every time would read +2.6 per 100 first serves in before the returner adjusts.
Ad court
| 1st serve | Now | Felix wins | v John | Matchup | Optimal |
|---|---|---|---|---|---|
| Wide | 46% | 75% | 83% | 85.0%±2.2 | 40% ▼ |
| Body | 6% | 63% | 70% | 70.5%±6.4 | 0% ▼ |
| T | 47% | 76% | 80% | 83.9%±2.4 | 60% ▲ |
Optimal v John Isner: +0.6±0.4 per 100 first serves (faults included) over the current mix. Serving wide every time would read +1.5 per 100 first serves in before the returner adjusts.
Return plan
Value of each return, in points per 100 returns against an average return of the same serve (direction, court, surface): the tour's result with that return, the returner's own edge with it, and what this server gives up when it comes back to that side. Returns with no charted direction are left out, so values compare with each other rather than with zero. Depth isn't a choice here: missed returns have no depth. Serve quality isn't charted, so a block through the middle partly reflects the serve that forced it.
John Isner returning
1st serve to the forehand
| Return | Now | Tour | Own | v Felix | Value |
|---|---|---|---|---|---|
| FH through the middle | 47% | +4.3 | −1.2 | −0.2 | +2.8±1.5 |
| FH down the line | 31% | +1.7 | −1.9 | −3.3 | −3.6±2.8 |
| FH crosscourt | 11% | +5.5 | +0.9 | −0.6 | +5.8±3.6 |
| FH slice through the middle | 5% | −4.2 | +2.2 | −1.3 | −3.3±2.1 |
| FH slice down the line | 4% | −4.3 | +0.6 | −1.0 | −4.7±3.1 |
Lean FH crosscourt: +5.3±3.4 per 100 returns v the current mix (1500 returns charted)
1st serve to the backhand
| Return | Now | Tour | Own | v Felix | Value |
|---|---|---|---|---|---|
| BH through the middle | 47% | +6.4 | −3.2 | +0.6 | +3.8±1.4 |
| BH crosscourt | 19% | +8.8 | −2.4 | −0.6 | +5.8±2.3 |
| BH down the line | 14% | +4.2 | −1.8 | −1.4 | +1.0±3.7 |
| BH slice through the middle | 9% | −4.2 | −1.4 | −2.0 | −7.7±2.1 |
| BH slice crosscourt | 7% | +0.5 | −4.8 | −2.6 | −6.8±2.7 |
Lean BH crosscourt: +4.3±2.1 per 100 returns v the current mix (1608 returns charted)
2nd serve to the forehand
| Return | Now | Tour | Own | v Felix | Value |
|---|---|---|---|---|---|
| FH through the middle | 46% | −3.5 | −2.6 | −0.3 | −6.4±2.1 |
| FH down the line | 42% | −1.8 | −4.5 | −2.8 | −9.1±3.9 |
| FH crosscourt | 10% | −0.2 | −5.4 | −5.6 | −11.2±4.0 |
| FH slice through the middle | 2% | −12.7 | −0.4 | −0.2 | −13.3±2.0 |
Lean FH through the middle: +1.8±2.0 per 100 returns v the current mix (367 returns charted, inside the 90% margin)
2nd serve to the backhand
| Return | Now | Tour | Own | v Felix | Value |
|---|---|---|---|---|---|
| BH through the middle | 46% | −2.9 | −2.8 | +0.1 | −5.7±1.4 |
| BH crosscourt | 26% | +1.0 | −3.3 | −1.5 | −3.8±2.2 |
| BH down the line | 14% | −0.2 | ±0.0 | +0.3 | +0.1±4.3 |
| FH inside-out | 7% | +1.0 | +1.9 | −2.8 | +0.1±3.3 |
| FH through the middle | 6% | −2.9 | −2.5 | −0.3 | −5.7±2.0 |
Lean BH down the line: +4.1±3.8 per 100 returns v the current mix (996 returns charted)
Felix Auger Aliassime returning
1st serve to the forehand
| Return | Now | Tour | Own | v John | Value |
|---|---|---|---|---|---|
| FH through the middle | 50% | +4.3 | −0.6 | −1.7 | +1.9±1.4 |
| FH down the line | 21% | +1.7 | −0.9 | −0.6 | +0.2±3.1 |
| FH crosscourt | 20% | +5.5 | −1.5 | −1.7 | +2.2±3.1 |
| FH slice through the middle | 6% | −4.2 | −1.3 | −1.6 | −7.1±2.0 |
| FH slice down the line | 2% | −4.3 | +0.1 | −1.7 | −5.8±3.1 |
Lean FH crosscourt: +1.4±2.6 per 100 returns v the current mix (1741 returns charted, inside the 90% margin)
1st serve to the backhand
| Return | Now | Tour | Own | v John | Value |
|---|---|---|---|---|---|
| BH through the middle | 39% | +6.4 | +1.5 | −2.2 | +5.8±1.5 |
| BH crosscourt | 34% | +8.8 | +0.1 | −0.1 | +8.8±2.2 |
| BH slice through the middle | 11% | −4.2 | −0.9 | −2.2 | −7.3±1.8 |
| BH down the line | 7% | +4.2 | +1.4 | +1.7 | +7.4±4.1 |
| BH slice crosscourt | 6% | +0.5 | −1.8 | +0.4 | −0.9±2.6 |
Lean BH crosscourt: +4.0±1.6 per 100 returns v the current mix (2015 returns charted)
2nd serve to the forehand
| Return | Now | Tour | Own | v John | Value |
|---|---|---|---|---|---|
| FH through the middle | 47% | −3.5 | −0.1 | −1.7 | −5.3±2.2 |
| FH crosscourt | 30% | −0.2 | −0.5 | −2.5 | −3.2±4.1 |
| FH down the line | 19% | −1.8 | −2.0 | −1.1 | −4.8±4.4 |
| FH slice through the middle | 2% | −12.7 | +0.3 | −1.0 | −13.4±2.0 |
| FH slice down the line | 1% | −9.4 | +0.1 | −1.5 | −10.9±2.5 |
Lean FH crosscourt: +1.6±3.2 per 100 returns v the current mix (403 returns charted, inside the 90% margin)
2nd serve to the backhand
| Return | Now | Tour | Own | v John | Value |
|---|---|---|---|---|---|
| BH crosscourt | 36% | +1.0 | −3.2 | −1.3 | −3.4±2.0 |
| BH through the middle | 34% | −2.9 | −1.3 | −3.1 | −7.3±1.5 |
| FH through the middle | 9% | −2.9 | −0.2 | −1.7 | −4.8±2.0 |
| BH down the line | 8% | −0.2 | +2.0 | −3.8 | −2.1±4.6 |
| FH inside-in | 6% | +0.6 | +1.4 | −2.5 | −0.6±4.2 |
| FH inside-out | 6% | +1.0 | −0.2 | −1.1 | −0.3±3.5 |
Lean FH inside-out: +4.2±3.4 per 100 returns v the current mix (1299 returns charted)
Rally plan
Edge, in points per 100 shots: the hitter's skill with the shot (own) plus how much the receiver usually gives up against it (theirs), both measured against the tour average.
John Isner
Favour
| Shot | Edge | Own | Theirs |
|---|---|---|---|
| FH volley to their forehand · rally | +8.9±5.1 | +4.3 | +4.6 |
| BH volley to their backhand · rally | +8.7±5.4 | +1.7 | +7.1 |
| FH volley to their forehand · serve +1 | +5.3±5.2 | +7.1 | −1.8 |
| FH slice to the middle · rally | +2.2±2.8 | +2.7 | −0.5 |
| FH to their forehand · serve +1 | +1.0±2.0 | +0.3 | +0.7 |
| FH volley to the middle · rally | +0.6±6.0 | −5.2 | +5.8 |
Avoid
| Shot | Edge | Own | Theirs |
|---|---|---|---|
| BH to their forehand · serve +1 | −11.2±3.8 | −9.4 | −1.7 |
| FH to their backhand · return +1 | −6.7±2.3 | −3.2 | −3.5 |
| FH to their backhand · rally | −6.3±1.3 | −5.8 | −0.4 |
| FH to their backhand · return | −6.3±2.1 | −3.1 | −3.2 |
| BH slice to their backhand · rally | −5.9±1.7 | −5.6 | −0.4 |
Felix Auger Aliassime
Favour
| Shot | Edge | Own | Theirs |
|---|---|---|---|
| BH to their forehand · serve +1 | +8.4±4.0 | +2.5 | +5.9 |
| BH to their forehand · rally | +6.3±2.7 | −0.8 | +7.1 |
| FH to their forehand · serve +1 | +5.0±1.9 | +0.5 | +4.5 |
| BH volley to their forehand · rally | +4.2±5.6 | +0.7 | +3.6 |
| BH volley to their backhand · rally | +4.1±5.7 | −2.3 | +6.4 |
| FH volley to their forehand · rally | +3.1±5.3 | −0.4 | +3.5 |
Avoid
| Shot | Edge | Own | Theirs |
|---|---|---|---|
| BH slice to their forehand · return +1 | −3.7±3.5 | ±0.0 | −3.7 |
| BH slice to the middle · return | −3.4±1.7 | −0.2 | −3.2 |
| BH slice to their backhand · return | −3.2±2.4 | −2.1 | −1.0 |
| FH slice to the middle · return | −3.0±1.9 | −0.5 | −2.5 |
| BH to the middle · return | −2.3±1.1 | +0.6 | −2.9 |
Against Felix Auger Aliassime-like opponents
| John Isner v | Matches | Serve pts won | Return pts won |
|---|---|---|---|
| All charted opponents | – | 70.5% | 26.5% |
| Players most similar to Felix Auger Aliassime | 3 | 66.8% | 19.4% |
| Felix Auger Aliassime (charted head-to-head) | 1 | 67.9% | 37.0% |
Similar by tactical fingerprint: Casper Ruud, Stefanos Tsitsipas, Arthur Fils, Tommy Paul, Alexei Popyrin, Zizou Bergs, Thanasi Kokkinakis, Lloyd Harris, J J Wolf, Leonardo Mayer. When two players have rarely met, their records against these lookalikes fill the gap.