Playing at Triple-A Las Vegas, top Mets prospect Zack Wheeler is just one level away from the big leagues. But the right-hander’s early-season results suggested he was still a couple steps from joining Matt Harvey in the big-league rotation. Wheeler took one of those steps yesterday. The 22-year-old struck out eight and held Reno to five hits and one run in 6 2/3 innings, leading the 51s to a 10-2 victory at Aces Ballpark. “I found my rhythm after first inning,” said Wheeler, who saw immediate results from an adjustment in his mechanics. “Once you get into a rhythm, things just kind of go. You don’t have to force anything or think too much.” After Wheeler piled up 18 walks in his first five starts, the Mets sent video of Wheeler from last season, when he dominated the Double-A Eastern League, and compared it to this year. They found Wheeler slightly turning his back to the plate and having to pick up the target again before delivering the pitch. He issued just one walk yesterday. “Once you see something like that, you have to make an adjustment,” Wheeler said. “We finally got some video in from last year and compared it to this year. We immediately saw the tweak I needed to make. ... It sharpened up my off-speed pitches and helped my fastball command.” Wheeler retired 11 in a row after pitcher Garret Mock singled in the second inning. The run ended on a one-out error in the sixth, but Wheeler easily set down the next two Aces. Mark Teahen singled to lead off the seventh and Wheeler exited after a two-out free pass. “That’s the best he’s thrown this year, absolutely,” 51s manager Wally Backman said. “The only walk was there in the seventh inning and he was a little upset with himself. “For him to see, after watching some film, the correction that needed to be made, I think that shows the quality of the individual. He’s an intelligent kid.”