Mark Leiter Jr. allowed a run over 5 1/3 innings of strong relief and the Chicago Cubs made the visiting Boston Red Sox pay for poor defense to win their fourth in a row, 3-1 on Saturday night.

Leiter was pressed into emergency service after the first seven pitches of the game.

Cubs starter Alec Mills struck out Jarren Duran to open the game, then allowed a double to Rafael Devers. However, that was the extent of his night, which ended due to reported lower-back pain.

Leiter (2-2) came on and stranded Devers. He ended up allowing just a sixth-inning run on Devers' double-play grounder, three hits and one walk while striking out five before leaving with two outs in the sixth.

Mychal Givens followed with two scoreless innings and David Robertson stranded two runners in the ninth to pick up a four-out save for Chicago, which has won seven of 10 and matched its longest winning stretch of the season. Robertson earned his 11th save.

Chicago's bullpen threw 3 2/3 scoreless innings during Friday's comeback win over Boston, which is 0-2 in July after going 20-6 in June.

Meanwhile, Boston starter Josh Winckowski (3-2), making his fifth career start, allowed two runs -- one earned -- on six hits, but only one left the infield. The right-hander also struck out a career-high six with a walk.

However, his teammates managed just five hits and went 1-for-7 with runners in scoring position. Duran went 2-for-4.

Chicago's first two runs came in the second inning, when the Red Sox defense suffered a mini breakdown. Back-to-back throwing errors from Devers and Winckowski on infield hits from Patrick Wisdom (2-for-4) and Nico Hoerner (2-for-4) gave Chicago a 1-0 lead. The hosts got another run on Narciso Crook's sacrifice fly.

The Cubs added some welcomed insurance in the ninth with Wisdom's two-out RBI single off Tanner Houck.

Chicago, which has also won four straight and six of eight at home, matched a season high by winning three consecutive series.