Ben Spies has completed a double victory on home ground at Miller Motorsports Park to make some headway into Noriyuki Haga's substantial World Superbike Championship lead.

Although he didn't have an interruption to contend with on this occasion, Spies was in similarly imperious form, leading from start to finish to complete his sixth win and his second double of the season.

With Haga finishing down in eighth position, to go with his ninth from the opening race, Spies has been able to reduce the chasm between himself and the championship leader by 35 points, bringing it down to a somewhat more manageable 53.

Having proven untouchable during the first race, Spies was certainly the man to beat from the start line, the Texan producing arguably his finest start of the season so far to slingshot into the lead of the race, ahead of fellow front row starter Fabrizio.

Just behind, Carlos Checa managed a good getaway from second to slot into third, ahead of Haga and Max Biaggi, the pair doing a fine job of bullying their way to the front of the field from their respective ninth and 16th place starting positions.

With clear track ahead of him, Spies quickly began asserting his authority as he pulled away from the pack, although Fabrizio was gamely hanging on as he attempted to match the Yamaha through the Utah circuit's twists and turns.

In turn pulling out a gap over those behind him, his advantage improved on lap four when third place Checa came crashing down at the Attitude chicane, bringing a frustrating end to what looked like being best weekend of the season so far.

His demise left Rea in third position, the Northern Irishman having capitalised on Biaggi's messy attempt to pass Haga for fourth, the pair losing out as the Ten Kate Honda slid through into position.

Still, while Rea could not pull away from the pack, he was able to show remarkable defensive nous against the series of rivals queuing up behind him. Haga, Biaggi and Kiyonari all tried their luck at one stage to get the better of Rea, but he was able to maintain tight lines and, significantly, get good drive out of the final corner to counteract any slipstream effect down the lengthy home straight.

Further back, some of the star performers from race one, Shane Byrne, Broc Parkes and Jamie Hacking, were having a tougher time. Byrne was running well in the early stages but would drop to the back of the field on lap five, while both Kawasaki riders found themselves outside the top twenty at the end of the opening lap. Worse was to follow for Hacking when he clipped the back of Luca Scassa's Pedercini ZX-10R, sending the Italian skyward and out of the race, while the American was delayed to the back of the field.

Back at the front, Haga's attempt at a podium finish began to falter as the race reached its midway point having fallen away from Rea and Haga, while Kiyonari, a charging Leon Haslam, Jakub Smrz and Shinya Nakano would also find their way through eventually.

Of those getting backed up behind Rea, Haslam was making the most prolific progress, forcing Kiyonari to sit up as he dived through to assume fourth position.

Indeed, the Stiggy Honda rider looked the most likely candidate to wrestle third from Rea's grasp, which he did momentarily on lap 17, only for the Ten Kate machine to slip back through at the start of lap 18.

However, just as Haslam was gearing up for a last lap challenge to secure third podium of the season for himself, he lost the front end of his machine on the run up to Attitude, putting him out of the race, much to his obvious disappointment.

At the same time, Spies was crossing the line to celebrate his second win of the day, five seconds up on Fabrizio after the Italian's spirited mid-race assault, in which he kept the gap to his rival pegged at less than two seconds, faltered towards the end.

Haslam's demise meant Rea was fairly comfortable as he crossed the line for his second podium in consecutive events, while the outcome also sees him overtake Haslam for fourth in the overall standings. He finished ahead of Biaggi and Kiyonari, who were also to capitalise from the Briton's error to secure top five results.

Smrz completed a decent weekend for himself in sixth, ahead of Nakano - bandaged up after his race one accident - and Haga, the championship leader having his first 'off' weekend this season as he fell away substantially from the fight ahead of him.

Tom Sykes kept his finishes ticking over in ninth, up from 21st on the grid, ahead of Byrne, whose charge back through the field would most likely have seen him fighting for the podium had it not been for his earlier delay. The same could be said for Parkes, who scythed his way past a number of rivals to finish 11th.

A forgettable weekend for Suzuki ended with Yukio Kagayama and Fonsi Nieto finishing line astern in 12th and 13th, ahead of series returnee Lorenzo Lanzi, while Haslam's late retirement would actually promote his Stiggy team-mate Jake Zemke up to 15th to score his first WSBK point.