Inging driver Tsuboi set a time of 1m26.187s around the 4.673km circuit in Oita Prefecture with just a few seconds left to go in Q2, finding nearly eight tenths over his previous best effort in Q1.
Despite most of his main rivals leaving it even later to set their best flying laps, Tsuboi was able to hang on to the top spot of the timesheets, earning his first series pole position in 35 attempts by 0.174s.
The driver who came closest to Tsuboi’s benchmark was Red Bull junior Lawson, who secured another front row start with a time of 1m26.361s in his Mugen-run car.
Sena Sakaguchi made it two cars from Inging inside the top three, the 23-year-old qualifying a further tenth back to equal his best starting position in Super Formula.
Fastest driver in his Q1 group, Suzuka winner Ritomo Miyata ended up fourth for TOM’S with a time of 1m26.480s, while Nirei Fukuzumi qualified a strong fifth for the renamed ThreeBond team.
Kondo Racing’s Kenta Yamashita finished just 0.013s adrift of Fukuzumi in sixth, having previously shown strong pace in first practice earlier on Saturday.
Tadasuke Makino was seventh-quickest for Dandelion Racing, while Toyota Hypercar driver Ryo Hirakawa finished nearly six tenths off pole position in eighth position.
Nobuharu Matsushita was next up in ninth for B-Max, while Hirakawa’s Impul teammate Yuhi Sekiguchi could fare no better than 10th.
Ren Sato qualified 11th for Nakajima Racing while Kazuto Kotaka will line up 12th after a crash at the very end of qualifying on his sole flying lap.
Three-time Super Formula champion Naoki Yamamoto qualified 13th for Nakajima Racing, having missed out on a spot in Q2 by just 0.049s.
He will be joined on the seventh row of the grid by TGM’s Toshiki Oyu, who was the biggest name to drop out in his Q1 group.
Oyu’s chances weren’t helped by Hiroki Otsu - replacing an unwell Tomoki Nojiri at Mugen - spinning and crashing rear-first into the barriers with less than a minute left, wrecking the fastest lap attempts of Oyu among others.
Although the session was restarted with three minutes added to the clock, Oyu was unable to set a time good enough to progress into Q2 and bid to replicate his Suzuka pole, ending up a season-worst 14th on the grid.
Otsu’s spin leaves the Mugen super-sub 22nd and last on the grid, a major blow to both the 28-year-old and championship leader Nojiri, who had to sit out the weekend after being diagnosed with a collapsed lung.
Autopolis Super Formula - Q2 results:
| Cla | # | Driver | Team | Time | Gap |
|---|---|---|---|---|---|
| 1 | 38 |  Sho Tsuboi |
JMS P.mu/cerumo-INGING | 1'26.187 | |
| 2 | 15 |  Liam Lawson |
Team Mugen | 1'26.361 | 0.174 |
| 3 | 39 | Sena Sakaguchi |
JMS P.mu/cerumo-INGING | 1'26.474 | 0.287 |
| 4 | 37 | Ritomo Miyata |
Vantelin Team TOM'S | 1'26.480 | 0.293 |
| 5 | 12 | Nirei Fukuzumi |
ThreeBond Racing | 1'26.508 | 0.321 |
| 6 | 3 | Kenta Yamashita |
Kondo Racing | 1'26.521 | 0.334 |
| 7 | 5 | Tadasuke Makino |
Dandelion Racing |
1'26.668 | 0.481 |
| 8 | 20 | Ryo Hirakawa |
ITOCHU ENEX TEAM IMPUL | 1'26.762 | 0.575 |
| 9 | 50 | Nobuharu Matsushita |
B-Max Racing Team | 1'26.852 | 0.665 |
| 10 | 19 | Yuhi Sekiguchi |
ITOCHU ENEX TEAM IMPUL | 1'27.064 | 0.877 |
| 11 | 65 | Ren Sato |
TCS Nakajima Racing | 1'27.092 | 0.905 |
| 12 | 4 | Kazuto Kotaka |
Kondo Racing | 1'44.559 | 18.372 |
| View full results | |||||
