Eugene Laverty boosted his hopes of securing the World Superbike title by winning a thrilling second race of the weekend at Laguna Seca on Sunday.
Having finished third in Saturday's first race, Laverty led early on in race two but then fell back to third.
The Aprilia rider moved up to second on lap 23 of 26 and then overtook Tom Sykes on the penultimate lap.
Laverty lies second in the series, 23 points behind leader Sykes with two rounds and four races remaining.
Kawasaki rider Sykes, from Yorkshire, has 361 points, with Toomebridge man Laverty on 338, Sylvain Guintoli on 337 and Marco Melandri on 319.
Laverty won the second race of the United States round from Davide Giugliano, Melandri and Sykes to remain in contention for the championship.
"I wasn't sure I could do that as I didn't have great grip but it just shows the power of the Aprilia," said Laverty after his victory.
"That was one of the best races of my life and I had to work so hard over the last few laps."
Laverty had qualified third fastest and lay fourth when race one was red-flagged and fifth when the opener was stopped for a second time.
The Toomebridge man was fifth for much of the 12-lap second re-start but moved up to secure a podium place with a strong performance on the final lap.
Kawasaki ace Sykes won the first Laguna Seca race from BMW rider Chaz Davies, with Melandri fourth and Laverty's team-mate Guintoli fifth.
A poor start saw Laverty occupy fifth position, although he had improved to fourth position when the red flags came out on lap eight of 26, with Guintoli leading.
Laverty lay fifth when the first re-start was brought to a halt but improved to clinch a rostrum place in the second re-start.
The final two rounds will be staged at Magny-Cours and Jerez in October.