Marcus Semien and Khris Davis connected early and Oakland's bullpen barely held off Jose Abreu and the Chicago White Sox late for a 5-3 win Wednesday that sent the AL playoff series to a deciding Game 3.
A's reliever Jake Diekman walked home a run in the ninth, then retired the big-hitting Abreu on a sharp grounder to end it and even the best-of-three wild-card matchup at 1-all.
The White Sox went 14-0 in the regular season against left-handed starters and beat southpaw Jesus Luzardo in the playoff opener.
Bassitt allowed one run on six hits in seven-plus innings during an impressive postseason debut as the AL West champion A's snapped a six-game postseason losing streak dating to 2013.
The right-hander, drafted by the White Sox before being traded to Oakland in December 2014, came in on a nice roll with an 0.34 ERA in September.
Things got interesting when Bassitt gave way to Liam Hendriks after a leadoff single to Tim Anderson in the eighth with a 5-0 lead. Yasmani Grandal hit a two-run homer one out later.
Hendriks surrendered a pair of two-out singles in the ninth and walked Yoan Moncada to load the bases. Diekman relieved and walked Grandal to bring home a run.
Abreu, a leading candidate for AL MVP, hit a hard grounder to second base as Diekman earned a tough save.
Oakland hit three consecutive one-out singles in the first against Dallas Keuchel, and rookie second baseman Nick Madrigal's fielding error allowed two runs to score.
Keuchel exited after 3 1/3 innings having allowed five runs - three earned - and six hits.
He couldn't hold down the slugging A's as Lucas Giolito did a day earlier taking a perfect game into the seventh inning of Chicago's 4-1 Game 1 victory.