PHOENIX -- Mike Lowell started warming up in the fifth inning. By the time the 10th inning came around, he and the strained ligament in his left thumb were ready.
"He didn't sit around all night," Boston manager Terry Francona said. "He stretched, hit, was in the cage. That's the type of guy he is. He honors his responsibility to the best of his ability no matter what the role."
Jason Varitek homered, doubled and drove in three runs for the Red Sox, who won their third straight to remain 10½ games ahead of the New York Yankees in the AL East.
"Today was another one-run game and that does nothing but build confidence," Varitek said.
Juan Cruz (2-1) walked Ortiz to open the 10th, and Kevin Youkilis and J.D. Drew both singled to load the bases. Cruz struck out Varitek before Lowell lifted a high fly to right on a two-strike pitch that Carlos Quentin caught, but his throw home was well wide of the plate.
"I think you have to change your game plan," said Lowell, whose left hand was wrapped in ice after the game. "If when you have two strikes you change your swing, you're not really helping yourself out."
The Diamondbacks appealed at third, saying Ortiz left for home early, but were denied.
"We laugh all the time, but David's a good baserunner," Francona said. "He's a big kid out there, but he knows how to run the bases when he needs to."
Hideki Okajima (2-0) pitched two innings, allowing a walk and striking out one, for the win in front of 49,826, the largest paid crowd in Chase Field history.
Jonathan Papelbon, making his first appearance in a week, allowed two baserunners in the 10th before finishing for his 14th save in 15 attempts.
Boston's bullpen held the Diamondbacks to one hit over the final four innings.
"Our at-bats from the fourth inning on weren't very good," Melvin said. "We made them work early on and we probably had one or two good at-bats the rest of the way. We can't just say, 'Here's the lead. Bullpen, hold it.' It's a one-run lead. They have too good a lineup to sit back and say, 'You guys do the work.' We've got to add on."
Youkilis walked to lead off the eighth against Brandon Lyon and was forced at second on J.D. Drew's grounder to first. Varitek followed with a double to the wall in left-center, scoring Drew to tie it at 3.
Varitek's sixth-inning homer, his seventh, had pulled Boston within 3-2 after Arizona opened a 3-0 lead after four innings.
"Owings threw the ball real well," Varitek said. "He had good stuff, but he made one mistake to me and we capitalized on it."
Mark Reynolds led off the fourth with a double down the left-field line off Julian Tavarez (3-5) and Drew followed with a line-drive homer just over brother J.D.'s head and the right-field fence to give the Diamondbacks a 3-0 lead.
Owings pitched out of trouble for much of the night and allowed two runs and seven hits over six innings.
"It's nice anytime you get the lead and it's even better when you can keep it," Owings said. "It's a great club we're playing, arguably the best in baseball."
Stephen Drew's hard slide at second after a leadoff single broke up a possible double play and allowed Quentin to reach on a fielder's choice. Miguel Montero doubled just inside the right-field line as Quentin broke for second, and the right fielder scored easily for a 1-0 lead.
Tavarez allowed three runs on six hits with a walk and five strikeouts.
- Boston LF Manny Ramirez, who was hit on the wrist Friday by a pitch from Arizona's Doug Davis, did not take batting practice and was scratched in favor of Eric Hinske. Francona said Ramirez will be a game-time decision for Sunday's series finale.
- The previous largest crowd in Phoenix was 49,707 for Game 6 of the 2001 World Series on November 3, 2001. The Diamondbacks' largest regular-season crowd was 49,548 on April 9 against Cincinnati, Arizona's home opener.
- Tavarez entered the game 0-1 with a 14.46 ERA over 10 appearances in Phoenix.
- Arizona LF Eric Byrnes went 0-for-5, ending his 15-game hitting streak and his streak of consecutive games reaching base at 31.