Kurt Busch set himself up as the man to beat in this weekend's Auto Club 400 in Fontana, California for this weekend's fifth round of the 2015 NASCAR Sprint Cup Series championship.

Busch was fastest by almost three tenths of a second in Friday's sole practice session and then went on to pip his Stewart-Haas Racing team mate Kevin Harvick to the pole position for Sunday's race, his fourth time on pole in Fontana - a new track record for the two-mile Auto Club Speedway.

It was pretty much the same again on Saturday, with Kurt Busch topping both of the day's 55-minute practice sessions. He posted a best time of the day of 38.479s (187.115mph) in the earlier of the day's outings, with a slower time of 38.925s (184.971mph) later in the day as temperatures rose.

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See full Saturday practice times from Fontana.

So far, the only time that Busch has not been on top of the timings screens was in the first round of qualifying on Friday when he was pipped to the top by Joe Gibbs Racing's Matt Kenseth and by his own SHR team mate Kevin Harvick, who is himself looking to complete a sweep of all three race wins of NASCAR's West Coast spring tour after back-to-back wins at Las Vegas and Phoenix.

Busch meanwhile is making only his second race start of the year, after being forced to sit out events at Daytona, Atlanta and Vegas while suspended by NASCAR over allegations of domestic abuse made by his former partner Patricia Driscoll.

Hendrick Motorsports' Jimmie Johnson and JGR's David Ragan were the nearest to matching Busch's pace in the early Saturday practice, while Richard Childress Racing's Paul Menard was 0.230s off Busch's pace in the later session, just ahead of Kevin Harvick.

There were no significant incidents in Saturday's two practice session, compared with Friday when Roush Fenway Racing's Greg Biffle scrapped the wall in turn 4 and JGR's Carl Edwards also subsequently losing control at the same part of the track and putting the #19 entry into the wall with enough force to send him to the backup car for the rest of the weekend.

Brett Moffitt also had a brush with the wall in qualifying on Friday evening, but not serious enough to need him to take to the backup #55 Michael Waltrip Racing car as he sits in for Brian Vickers who has been sidelined with new health issues.

Also on Friday, NASCAR officials said that they had taken possession of the truck arm off the Circle Scott Racing #33 Chevrolet driven this weekend by Brian Scott after finding a technical infraction during opening inspection.

Officials said they would take the part back to the NASCAR Research and Development Center in Concord, North Carolina, for further examination and would announce any findings and possible penalties early next week.

See full Saturday practice times from Fontana.

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