(SportsNetwork.com) - The Baltimore Orioles will look for Chris Tillman to extend some impressive streaks on Saturday evening when they resume a three- game set with the Boston Red Sox.

Tillman has not lost since July 12, going 5-0 with a 2.01 earned run average in his last 12 starts, and has yielded three earned runs or fewer in each of his last 19 outings.

The right-hander is 12-5 with a 3.29 ERA on the year and Baltimore is 10-2 over his unbeaten streak. That includes Baltimore's 3-2 win over the New York Yankees on Sunday in which Tillman got a no-decision despite giving up one run over 6 2/3 innings.

Tillman is 6-3 in 15 previous starts against Boston with a 2.70 ERA.

Boston's David Ortiz is only 2-for-24 lifetime versus Tillman with five walks and six strikeouts. The slugger added to his impressive career resume in Friday's 5-3 victory, going deep twice and driving in three runs.

Ortiz now has 34 homers and 102 RBI on the season, recording his eighth 30- homer, 100-RBI season to surpass Ted Williams for the club's all-time record.

Ortiz's two-run homer in the 10th inning helped Boston snap a three-game slide.

"I'm a positive person and try to come in and get things down," said Ortiz. "I don't focus on how we've struggled this season, I just come in and do my best every night."

Yoenis Cespedes also homered for the Red Sox, who had lost four of five coming in.

Nelson Cruz was 3-for-5 with an RBI for the AL-East champion Orioles, who had a four-game winning streak snapped.

Kevin Gausman allowed three runs -- two earned -- on seven hits in five innings as he yielded back-to-back homers to Ortiz and Cespedes in the fourth.

"I felt good but I just left some pitches up," said Gausman. "I never want to give up back-to-back home runs, but that one Cespedes hit, that was a pretty line-drive home run."

Rubby De La Rosa will try to secure his first victory since Aug. 10 tonight for the Red Sox. He is 0-3 in six starts since and has gotten through the sixth inning just once over that span.

De La Rosa lost his second start in a row last Saturday at Kansas City, tagged for five runs on six hits over four innings. That dropped the young hurler to 4-7 this year with a 4.31 ERA in 17 starts.

The righty is 0-2 with a 7.11 ERA in two games (1 start) versus Baltimore.

Baltimore is 10-7 this season versus the Red Sox.