Xander Bogaerts drove in both runs, including a go-ahead sacrifice fly with the bases loaded off closer Trevor Rosenthal in the ninth inning. Three of Rosenthal's six losses have come when he's entered with a game tied in the ninth. The double snapped an 0-for-15 slump for Bogaerts, and the RBIs were his first since July 29.
"I thought he wanted to get ahead of me with a fastball so he could use his off-speed pitches," Bogaerts said. "So I just went in there and keyed on the fastball."
Junichi Tazawa (2-3) worked a perfect eighth, and Koji Uehara worked around two hits in the ninth for his 23rd save in 25 chances. Boston won for just the third time in 14 games and snapped St. Louis' three-game win streak.
Rosenthal (1-6) was working in his fourth consecutive game in a span of five days.
"I felt good -- I felt like I was making some good pitches," Rosenthal said. "I felt good the whole inning. There was no question I was ready to go."
Kelly had worked seven innings only twice in 22 starts for St. Louis the past two seasons, and Miller got that deep for just the eighth time in his 54 career starts. Kelly got a nice ovation while he walked to the bullpen to begin warmups, as hundreds of fans stood. There were more cheers when he stepped onto the mound for the first time and before his first at-bat, which lead off the third.
The crowd cast yet another vote against the trade that brought starter John Lackey but came as a shock in the clubhouse. They cheered Kelly's infield hit after the Red Sox successfully challenged an out call by first base umpire Gary Cederstrom.
The Red Sox loaded the bases with none out in the ninth against Rosenthal, via a single by Yoenis Cespedes, a double by Mike Napoli and an intentional walk to pinch hitter David Ortiz. Bogaerts lined out to center for a sacrifice fly and the lead.
The first pitch was delayed 1 hour, 3 minutes by rain.
Red Sox: GM Ben Cherington is optimistic Allen Craig will be back from a left foot strain this season, but Craig is set to visit Dr. James Andrews for a second opinion.
The Cardinals mustered three hits against Kelly. Two of them were in the first. Matt Carpenter led off the first with a double and scored on a two-out hit by Matt Adams for the lead.
The Red Sox tied it at 1 in the fourth on a pair of two-out hits -- Daniel Nava's single and a double by Bogaerts off the wall in center that Jon Jay just missed. Miller retired his last 10 in order.
Jay tracked down Napoli's drive at the wall to end the sixth and keep it tied, and Cespedes tracked down Johnny Peralta's liner at the track in left in the sixth, both on balls that probably would have been homers had there been more humidity. Bogaerts robbed Carpenter of an RBI in the second with a diving stop to his left at short and a toss to second for an inning-ending force play.
Cardinals ace Adam Wainwright (13-6, 2.26) opposes Brandon Workman (1-4, 4.08) in the series finale. In the World Series, Wainwright was 0-2 with a 4.50 ERA, and Workman did not allow an earned run in 3 1/3 innings of relief.
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ST. LOUIS, MO - AUGUST 6: Members of the grounds crew pull the tarp over the field during a rain delay prior to a...