Chaz Davies returns from injury to win in Laguna Seca

The Ducati rider suffered a fractured vertebrae and bruised thumb following a crash during the opening race in Misano last month, which had left the Welshman facing a battle to return to the track for the United States round.

However, Davies produced a composed display in the California heat as during the 12th lap he cut inside both Tom Sykes, who had again claimed superpole, and Rea before then fending off attacks from the Kawasaki team-mates to maintain a 1.2 second lead for a fourth win of the 2017 campaign.

Afterwards, Davies took a lap of honour with a stars and stripes 69 'Kentucky Kid' flag in tribute to Nicky Hayden, the American MotoGP world champion who died in May from injuries sustained in a road traffic accident.

Ducati team-mate Marco Melandri was fourth, with Spaniard Xavi Fores taking fifth for BARNI Racing.

Ireland's Eugene Laverty, meanwhile, spun out his Aprilia on lap 10, while Pata Yamaha rider Alex Lowes went off after six circuits.

Stefan Bradl was partnered by American Jake Gagne as Red Bull Honda returned to a two-man team for the first time since Hayden's death.

Rookie Gagne, competing in his first World Superbike race, finished 15th - a improvement of three places from the starting grid position - while German Bradl was 11th some 44.961 seconds off the pace.

Despite not being able to wrestle back Saturday's race lead from Davies, Northern Irishman Rea remains very much in control at the top of the rider rankings.

Rea is now 54 points clear of Sykes, who had earlier snatched what was a third consecutive place at the front of the grid with a hot lap of 1:22.476 in the closing moments to equal Troy Corser's record of three poles at Laguna Seca.

Davies, meanwhile, sits third on 210 points and 106 adrift of Rea heading into Sunday's race two.