The Red Sox’ fortunes against left-handers it seems have taken a turn for the better. As recently as 10 days ago the team’s mighty struggles against southpaws even those with less-than-dominant stuff were a noteworthy concern as the Sox headed into the final six weeks of the regular season. But in their last eight games — five of which have been against lefty starters — that hasn’t been the case. They have hit .341 in those eight games while getting on base at a .400 clip and slugging .652. The Red Sox have emerged victorious in four of the five games against southpaws the only loss being the Yankees’ come-from-behind win Aug. 18 which featured them getting to CC Sabathia for six runs in 5 1/3 frames. The most recent game in that stretch came Tuesday night at Fenway Park when the Red Sox chased left-hander Wei-Yin Chen in the fourth inning of a 13-2 win over the Orioles. The Red Sox hit him around for eight runs on eight hits (two home runs) and three walks in 3 2/3 innings to take the opener of the three-game mid-week series. Beating up Chen the way the Sox did is no small task. The second-year Taiwanese import who finished fourth in American League Rookie of the Year voting in 2012 owned a 3.19 ERA 1.15 WHIP and .244 opponents’ batting average when he woke up Tuesday. In 16 starts this season he had only allowed more than three earned runs in a given start twice. The Sox however came out of the gates swinging. After one run in the first and two in the third courtesy of a Shane Victorino homer they blew it open with five in the fourth inning.