DeRosa homered with one out in the 12th inning and scored the other Texas run Wednesday night in a 2-1 victory over the Baltimore Orioles.
"You knew somebody was going to have to pop one," said DeRosa, in only his fourth game back from the disabled list. "I was just worried when I committed that error."
The 12th inning started with DeRosa's fielding error that allowed Miguel Tejada to reach base. But Rick Bauer (2-1) then got Jay Gibbons to ground into a double play before Ramon Hernandez grounded out.
"I didn't want that error to get them going," DeRosa said. "On that double-play ball, I breathed a sigh of relief."
DeRosa ended the game on a full-count pitch off John Halama (1-1). The homer to right-center gave the Rangers their fifth straight win -- and 10th in 13 games.
"Mark's giving us a shot in the arm," manager Buck Showalter said. "He's such a hard-worker, such a professional. You like to see him get a return."
DeRosa has been a primarily a utility player during his career, playing from 1999-2004 with Atlanta before joining the Rangers last season. When Texas traded four-time All-Star second baseman Alfonso Soriano last offseason, DeRosa was a candidate to be the starter.
Texas went instead with rookie Ian Kinsler, who was hitting .476 when he dislocated his thumb the second week of the season. But DeRosa had a sprained left ankle and also ended up on the DL.
"It was tough, emotionally frustrating," DeRosa said.
Since returning, DeRosa is 8-for-15 with four doubles and two homers.
DeRosa started the third with an impressive defensive play. He went far to his left and dived to stop a short hopper, then threw from his knee to get Gomez out.
Gibbons homered for the only run for the Orioles, who have lost eight of their last 11. Tejada remained the majors' top hitter (.405) despite going 0-for-5.
"It was a great game. We played well," Orioles manager Sam Perlozzo said. "Somebody had to lose the game sooner or later."
Both teams had two runners on in the 10th.
Chris Gomez lined out for Baltimore after consecutive two-out singles. After rookie shortstop Brandon Fahey bobbled a potential double-play grounder in the bottom of the 10th, Mark Teixeira grounded into an inning-ending double play.
John Koronka, the rookie left-hander acquired from the Chicago Cubs on March 31, got 14 groundball outs with four strikeouts and no walks over 8 1/3 innings -- the longest outing by a Texas pitcher this season. That wasn't good enough for his fourth win, though he left to a standing ovation, a rarity in Texas.
"I didn't want to come out of the game," Koronka said. "Hearing the crowd was great."
Baltimore starter Daniel Cabrera allowed one run and six hits over seven innings.
Gibbons' seventh homer came with two outs in the fourth.
"I was thinking about that all night, that I just made one mistake," Koronka said.
Conine didn't score, making the final out of the fifth when he got caught in a rundown between third base and home plate. Catcher Rod Barajas bluffed a throw at Fahey when he took off running from first on a stolen-base attempt.
"You try to see if you can't steal a run there," Perlozzo said.
- Demoted Rangers closer Francisco Cordero worked a perfect 11th.
- Cabrera took over the AL lead with 25 walks, one more than Tampa Bay's Seth McClung.
- Orioles C Javy Lopez missed his sixth straight game because of back spasms.
- Barajas had a sacrifice bunt for the second straight night. That's five sac bunts in 28 games for the Rangers this season -- four shy of last year's total.
- Baltimore is 1-8 in games started by left-handers. They've lost eight in a row since beating Tampa Bay and Scott Kazmir on opening day.
- Texas starters haven't lost in the last 16 games. They are 6-0 in that stretch.