Arizona (40-37) has a four-game lead over the second-place Los Angeles Dodgers in the NL West, but since May 20, the Diamondbacks are batting a major league-worst .220 and have baseball's fourth-worst record at 12-21.

On Monday, the Diamondbacks defeated the Red Sox 2-1, as they broke a scoreless tie in the seventh inning with Chris Young's RBI double and Chris Snyder's run-scoring groundout.

While Arizona still didn't bust out of its offensive struggles against Boston's Josh Beckett, Melvin was impressed with the way his team played in a tough environment like Fenway. The Diamondbacks, who were swept at Minnesota over the weekend, won for just seventh time in their last 24 road games.

"It's one of the best games we've played," Melvin told the team's official Web site. "It's one of the best games feeling-wise that we've had all year.

"I think they could put Minnesota in the past and just go out there and try to play off the adrenaline and off the emotion of this ballpark."

Boston (47-32), meanwhile, dropped to 1-3 on its current six-game homestand after winning 17 of its previous 19 at Fenway.

The Red Sox, who are second in the AL in runs (396) and batting average (.278), couldn't get anything going against Arizona's Dan Haren on Monday, and finished with just four hits.

Adding to Boston's frustration, first baseman Kevin Youkilis left the game before the top of the fifth inning after getting hit under the right eye by Mike Lowell's one-hop throw during infield warmups. The 2007 AL Gold Glove winner was taken for "a precautionary CT scan."

"Well, I felt terrible about it," Lowell said. "I thought it hit him in the side of the head but, afterwards, I saw him shaken up and touching his eye."

Youkilis, who could be back in the lineup for this game, has been one of the Red Sox's hottest hitters with a .393 average (11-for-28), four homers and eight RBIs in his last eight games. He homered twice in Sunday's 5-3 victory over St. Louis, including a game-winning, two-run shot in the 13th inning.

Boston's Justin Masterson (4-1, 3.00 ERA) takes the ball Tuesday as he looks to continue an impressive start to his rookie year.

Masterson has been given a spot in the starting rotation due to injuries to Daisuke Matsuzaka and Bartolo Colon, and has thrived. Masterson has yielded two runs or less in four of his six starts this season, and opponents are batting .176 against him.

On Wednesday, the right-hander beat Philadelphia as he gave up two runs, four hits and two walks in five innings of a 7-4 win.

The Diamondbacks counter with Doug Davis (2-3, 3.65), who looks to continue his recent dominance - and get a win.

Davis has been brilliant in his last two outings, but did not receive a decision either time. He allowed one run and three hits in six innings while striking out a season-high eight in a 2-1 win over Oakland on Thursday. On June 13, the left-hander struck out seven in seven innings of a 1-0, 10-inning victory over Kansas City.

Davis is winless since May 23, his first start after spending more than six weeks on the disabled list recovering from thyroid surgery.

This will be Davis' first start at Fenway Park since yielding five runs and eight hits in seven innings of a 6-2 loss for Texas on Aug. 4, 2001. Last season, he gave up five runs, six hits and five walks in four innings of a 10-3 loss to the Red Sox on June 8.