Red Sox 3, Orioles 2: Pinch hitter Jonathan Herrera delivered a walk-off RBI single as host Boston outlasted Baltimore in the opener of a day-night doubleheader.Jonny Gomes led off the bottom of the ninth inning with a pinch-hit infield single before he was bunted to second by David Ross. Herrera, hitting for Jackie Bradley Jr., dumped a broken-bat base hit into shallow right field and Gomes slid home well ahead of the throw to snap a three-game slide for the Red Sox.Jon Lester allowed only two unearned runs and struck out seven in eight stellar innings and Stephen Drew had a solo homer for Boston, his first of the year. Miguel Gonzalez yielded two runs (one earned) in eight innings for Baltimore before T.J. McFarland (1-2) came on in the ninth and took the loss.Drew started the scoring with a shot into the Baltimore bullpen in right in the bottom of the second and Bradley doubled and scored on an error later in the frame to make it 2-0. Boston gave the runs right back with two errors in the third, the second by third baseman Xander Bogaerts, who booted a potential inning-ending grounder to allow both runs to come across.Lester stranded runners at the corners in the fifth and Drew began a spectacular double play to end the top of the eighth. Koji Uehara (4-2) got the win after striking out two in a perfect ninth as Boston improved to 15-18 in one-run games.GAME NOTEBOOK: Red Sox DH David Ortiz was out of the lineup as he returned from a family commitment in the Dominican Republic but is expected to be available for the nightcap. ... Lester is 3-0 with a 0.96 ERA over his last five starts. ... Orioles RH Ubaldo Jimenez opposes Red Sox RH John Lackey in the second game, scheduled to begin at 7:15 p.m. ET.