Orioles 2, Red Sox 1: Nelson Cruz hit a go-ahead solo homer in his team debut as Baltimore edged visiting Boston in the season opener.

Chris Tillman allowed a run and seven hits while battling through five innings and left-hander Zach Britton (1-0) picked up the win with two strong innings of relief for the Orioles. Cruz, who signed as a free agent over the winter, scored a run in the second before putting Baltimore on top in the seventh.

Grady Sizemore played his first major-league game since Sept., 2011 and provided the Red Sox’s lone run with a solo homer among two hits. Jon Lester (0-1) struck out eight while surrendering two runs in seven frames for Boston.

Cruz snuck across in the second when Delmon Young grounded into a double play and the Red Sox failed to take advantage of several chances in the early innings before Sizemore lifted a fly to deep right that just made it over the high wall to knot it at one in the fourth.

Cruz led off the bottom of the seventh and slammed a first-pitch fastball into the bleachers in left to give the Orioles a 2-1 lead. Boston left two runners on in the eighth and Tommy Hunter worked around a single and a hit by pitch in the ninth to pick up the save.

GAME NOTEBOOK: Xander Bogaerts, 21, went 1-for-3 while becoming the youngest Red Sox Opening Day SS since Everett Scott in 1914. … Boston RF Shane Victorino (hamstring) was placed on the 15-day disabled list and OF Jackie Bradley Jr. was added to the roster. … Baltimore 3B Manny Machado (knee) took part in pregame ceremonies but will head back to extended spring training on Tuesday to continue his rehab.