On June 5, 1986, Buckner picked up his 1,000th career RBI on a ground out in a 7-5 road loss to the Milwaukee Brewers. On August 21, he again had five hits in a blowout 24-5 road win over the Cleveland Indians. In September, he hit .340 with 8 home runs and 22 RBI, while missing just 3 games in spite of chronic ankle soreness. Dave Stapleton, the Red Sox first baseman prior to the acquisition of Buckner, began seeing more playing time as a late-inning defensive replacement in September and October. Meanwhile, Buckner became the first major league player to wear Nike high-top baseball cleats professionally in an effort to relieve pressure on his ankles. That season, Buckner hit a career-high 18 home runs, drove in more than 100 runs for the second season in a row, and was a key member of the team that won the American League East by 5-1/2 games. He entered Game 5 of the 1986 American League Championship Series batting just .111 in the Series, and was 0–for–3 in the game when he singled to start a ninth-inning rally which was capped off by Dave Henderson's famous home run. He went 3–for–6 in the final 2 games as the Red Sox came back from the brink of elimination to defeat the California Angels and win the American League pennant.