Cruz hit his third home run of the season, a solo shot that produced his 12th RBI and his eighth against the Red Sox.
The Orioles had gone four straight games without a home run. Cruz delivered their 10th of the season.
Did I jinx them earlier by mentioning the streak?
Chris Davis followed with a walk, extending his streak of reaching base to 16 consecutive games. Adam Jones singled and Matt Wieters delivered an RBI single to right field.
Wieters is now 14-for-38 (.368) with two home runs and seven RBIs from the left side of the plate.
J.J. Hardy followed with a sacrifice fly for his fourth RBI of the season. David Lough flied to deep right to end the inning on Peavy's 24th pitch.
Ubaldo Jimenez, looking to take some of the air out of his 7.31 ERA, walked Grady Sizemore leading off the bottom of the first before retiring the next three batters. The Red Sox worked him for 25 pitches, however.
The evening began with a moving pregame ceremony honoring Marathon victims, survivors and first responders. Both teams lined up on the field for the national anthem and a large American flag was draped over the Green Monster.
Update: Jimenez didn't allow a hit until Jonny Gomes doubled with two outs in the fourth. He's working on a two-hit shutout through the fifth with his pitch count at 88.
Jimenez's ERA has gone from 7.31 at first pitch to 5.57.
David Lough's ground rule double scored Wieters in the fifth and increased the lead to 4-0. Lough was 4-for-34 before that hit.
Wieters is 2-for-3 tonight and 15-for-40 (.375) from left side of the plate this season.