Mark Martin can't be stopped.
After earning the pole position on Friday and earning the top spot in Saturday's early practice, the 54-year-old veteran again found himself atop the leaderboard in the afternoon session in prep for Sunday's Subway Fresh Fit 500 Sprint Cup Series race at Phoenix International Raceway in Avondale, Ariz.
Martin's top speed of 134.248 mph, achieved on his seventh and final lap, was followed by Kyle Busch's 133.904 just shortly after the Joe Gibbs Racing driver notched the pole for Saturday evening's Nationwide Series event.
Reigning Sprint Cup Series champion Brad Keselowski turned his 31st lap in 26.926, placing him third on the leaderboard. The top 5 was rounded out by Carl Edwards (133.601 mph, starting 7th Sunday) and Clint Bowyer (133.526, 3rd).
Kasey Kahne, slated to start alongside Martin in the front row, was eighth in the second practice session with a time of 27.015 on his fifth lap.
Denny Hamlin, winner of last season's early Phoenix race, suffered engine trouble before the final practice and will start in the back of the pack on Sunday. He was 15th on the leaderboard at the end of the day.
Tony Stewart ran the most laps -- 56 -- and finished up practice for Sunday's event by placing seventh.
Daytona 500 winner Jimmie Johnson was 14th, while Daytona pole winner Danica Patrick bumped the wall hard at one point and earned the 34th fastest speed.
Early practice recap
Mark Martin continued to turn in blazing speeds in the desert, following up his pole position secured on Friday with a top practice speed of 135.45 mph in the first Saturday test run ahead of Sunday's Subway Fresh Fit 500 at Phoenix International Raceway in Avondale, Ariz.
The 54-year-old, who earned his 56th career pole, ran his fifth lap with a best time of 26.578. He was third in yesterday's practice.
Daytona 500 champ Jimmie Johnson maintained his hot start as well, turning in the fourth-fastest lap on the 1-mile oval after earning the third-overall spot in qualifying.
Kasey Kahne checked in at 22nd on Saturday, but figures to be in a good spot after running the most laps in practice Friday and will start alongside Martin in second position on Sunday.
Matt Kenseth, Friday's practice leader, dropped down the leaderboard in qualifying (ninth) and Saturday's early practice (10th). His Joe Gibbs Racing teammate, Kyle Busch, will start fourth on Sunday and made the early Saturday practice count, checking in as the runner-up on the leaderboard with a best speed of 135.201.
Denny Hamlin, the 500-kilometer race's defending champ, was 12th with a time of 26.798.
Kevin Harvick, November's 2012 Advocare 500 at PIR winner, ran the most laps -- 47 -- in the practice session, notching the fifth-fastest time.
Rookie Danica Patrick, who will start 40th on Sunday, turned in a best lap speed of 132.553, placing her 35th overall.
The second practice of the day is at 3 p.m. ET on Speed.
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