With Matsuzaka winning his fifth straight decision, Boston routed Atlanta 13-3 in the opener of a day-night doubleheader Saturday, boosting its AL East lead to 10½ games, its largest ever at this point in the season.
Lowell led Boston's season-high 18-hit attack with four hits, including a grand slam, and five RBI on a drizzly day. That increased his batting average to .333 and gave him 35 RBI in 39 games.
What skills contribute to his fast starts?
"If I knew, I'd use them in July, August and September," he said.
Last season, his first with Boston, Lowell was batting .331 on May 19 but finished at .284. Two years before that, with Florida, his average of .343 on May 19 dropped to .293 by the end of the season.
But Lowell anticipates no such drop-off in his team's success, especially with cleanup hitter Manny Ramirez hitting just .255 with six homers.
"Manny still hasn't gotten hot like you've seen him when he can just basically carry a team for like 10 days at a time," Lowell said. "We're playing good baseball, but I think we can actually do a little better."
The Red Sox (29-12) won for the 10th time in 12 games while the Braves have lost five of six.
In its last series, Boston took three of four games from defending AL champion Detroit. The Red Sox opened that series with a 7-1 win last Monday behind Matsuzaka's first complete game in the majors.
Matsuzaka (6-2) felt he could have gone nine innings again Saturday.
"I think I can probably throw between 140 and 150 pitches," he said through a translator after throwing 104. "The manager came in and spoke to me and said that, given our big lead, go and get some rest."
He struck out six and allowed nine hits in eight innings. He didn't issue a walk for his second straight outing. Kyle Snyder pitched the ninth.
"He just moves the ball around so much," Atlanta's Jeff Francoeur said of Matsuzaka. "He's got so many pitches. Nothing seems to go straight. ... When he got a big lead, you could see he was getting more confident."
Francoeur did go 3-for-3 against him, snapping a 1-for-14 slump.
Matsuzaka had allowed just five singles in six scoreless innings before giving up three runs in the seventh on a double by Chipper Jones, an RBI single by Jarrod Saltalamacchia and Francoeur's seventh homer of the season.
Julio Lugo, Kevin Youkilis and Wily Mo Pena also homered for the Red Sox, who knocked Anthony Lerew (0-2) out of his third major league start after just two innings. Youkilis extended his hitting streak to a career-high 12 games and Lowell's reached 10 games.
"I've had a little soreness in my elbow the last month or so," Lerew said. "I've just got to get some treatment on it and see what's going on in there."
After Lugo's two-run double made it 12-0 in the sixth, fans mocked the Braves by doing the tomahawk chop that Atlanta spectators do when the team does well.
Lugo started Boston's attack by leading off the first with his third homer of the season. Youkilis hit his fifth homer, a two-run shot in the second. Lowell's eighth homer, his sixth career grand slam, made it 7-0 in the fifth.
The Red Sox added five runs in the sixth on an RBI single by Lowell and two-run doubles by Coco Crisp and Lugo.
Lowell needed just a triple to hit for the cycle.
"The triple's always a tough one for me," he said. "I think I need a collision in center field and a couple of medics out there."
Manager Terry Francona began resting starters when he put Pena in left field in place of Ramirez to start the seventh. Pena then hit a solo homer, his third, in the bottom of the inning.
- The doubleheader was caused by Friday night's rainout.
- Of the 28 runs Matsuzaka has allowed, 20 have come in just seven innings.
- The Red Sox batted around in both the fifth and sixth innings.
- Lowell's grand slam was the second by Boston this season. Pena hit one on April 26 to give Boston a 5-2 win and erase Baltimore's 2-1 lead.
- Lowell also came up with the bases loaded in the first and flied out.
- Former Red Sox SS Edgar Renteria had three hits for the Braves.
- Matsuzaka threw 67 pitches in his first six innings. Atlanta reliever Chad Paronto threw 42 pitches in 1 1/3 innings.