Adam Dunn clubbed a three-run homer to help the Chicago White Sox hand Boston's Jon Lester his first loss of the season with a 6-4 win in the opener of a three-game set at U.S. Cellular Field.
Dylan Axelrod (2-3) tossed six strong innings for the White Sox, who snapped a two-game slide and won for the fifth time in their last seven games. Axelrod held the Red Sox to four hits, with the lone hiccup being a two-run homer by Jarrod Saltalamacchia.
Lester (6-1), meanwhile, was tagged for six runs -- five earned -- on seven hits over six frames. All six Chicago runs were scored with two outs.
"He still kept us in the game," Saltalamacchia said of his battery mate.
Boston had won five games in a row.
Down five runs at one point, the Red Sox closed the gap to 6-4 in the seventh. Matt Thornton relieved Axelrod and promptly walked the first two batters he faced. David Ortiz and Mike Napoli came around to score when Will Middlebrooks sent a one-out double off the wall in left field. Thornton settled down on the mound, recovering to retire Stephen Drew and Saltalamacchia.
Chicago's Jesse Crain pitched around a walk in the eighth, then Addison Reed overcame a leadoff single by Napoli in the ninth to earn his 15th save.
The White Sox jumped on Lester, building a 5-0 lead after two innings.
Lester retired the first two batters he faced in the opening frame before Alex Rios extended his career-best hitting streak to 15 games with a single. After a walk to Paul Konerko, Dunn crushed his 11th homer of the year, a smash to right field.
"It's nice to jump out to a lead and hold on to it," White Sox manager Robin Ventura said.
The second inning began the same way, with the Boston left-hander getting two outs with relative ease. Tyler Greene, Alejandro De Aza and Alexei Ramirez then strung together three straight doubles that produced two runs.
Saltalamacchia put Boston on the board in the third, but Dayan Viciedo singled home Ramirez, who had reached on an error, to put Chicago up 6-2 in the fifth.
Lester was trying to become the first Red Sox left-handed starter to begin 7-0 since Roger Moret opened 10-0 in 1973 ... Boston right fielder Shane Victorino left in the sixth with left hamstring tightness ... Chicago had lost four of its previous five homes games ... Boston second baseman Dustin Pedroia extended his hitting streak to 12 games with a leadoff single in the fourth ... The Red Sox activated reliever Andrew Bailey from the 15-day disabled list. Bailey had been sidelined since late April with a right biceps strain. The club made room for Bailey by optioning pitcher Jose De La Torre to Triple-A Pawtucket after Sunday's game in Minnesota ... Boston went 6-2 against the White Sox last year.