Ryo Hirakawa notched up his maiden Super Formula victory at Motegi, as Nick Cassidy finished on the podium to snatch the championship lead from Naoki Yamamoto.
When the 51-lap race got underway, Alex Palou led cleanly from pole position and started building a small gap up front, in what appeared to be a repeat of his lights-to-flag victory at Fuji.
However, Hirakawa slowly started cutting into Palou’s advantage and was right on the Nakajima Racing driver’s tail by lap 10 of 57.
It took another 13 laps for Hirakawa to pass Palou, the Impul driver sweeping around the outside coming out of the bridge complex to take the lead.
After clearing Palou, Hirakawa disappeared into the distance, taking the chequered flag by 2.972ss from second-placed Kamui Kobayashi.
Kobayashi got a brilliant launch from seventh on the grid to pass both Tomoki Nojiri and Hiroaki Ishiura into Turn 1, and then dispatched Red Bull junior Lucas Auer later on the opening lap to move into fourth.
The KCMG driver reeled in Dandelion’s Nirei Fukuzumi in the second half of the race, and was able to jump Palou with a later pitstop to finish second.
Cassidy started only 12th on the grid but chose to get rid of his medium tyres as early as lap 4, giving himself maximum track time on the faster soft compound.
That strategy turned to be a masterstroke as he found himself fifth on track after most of the pitstops were complete.
On the faster but worn-out soft tyres, Cassidy made light work of Fukuzumi, who ran wide at Turn 11 shortly after his pitstop, and then passed Palou with six laps to go to score his third podium of the season.
The result elevates Cassidy to the top of the standings, as Yamamoto was unable to score points in a nightmare race for the reigning champion.
Yamamoto had qualified eighth but stalled on the grid, forcing him to start from the pitlane.
Although he adopted a similar medium-soft strategy as Cassidy, he could only finish ninth, missing on a points finish by just 0.261s.
Yamamoto’s team-mate Fukuzumi finished fifth, ahead of last year’s winner Hiroaki Ishiura (Inging).
Auer dropped to seventh in a relatively sombre outing for the B-Max by Motopark driver, while Tomoki Nojiri grabbed the final championship point in eighth.
Red Bull junior Patricio O’Ward stalled on the way to his grid spot, which led to the race being delayed by five minutes and the race distance to be shortened by a lap.
He was allowed to start from the back alongside the similarly-stalling B-Max/Motopark car of Harrison Newey, and charged his way through the field on a two-stop strategy to finish 14th despite slowing momentarily on track while battling with Artem Markelov and Yamamoto.