Beckett (2-0) pitched a five-hitter to extend his streak of scoreless innings to 15, and Juan Encarnacion hit his second grand slam of the week to help Florida beat the Washington Nationals 8-0 Sunday.
The complete game was just the second for Beckett since he pitched a five-hit shutout to beat the New York Yankees in Game 6 of the 2003 World Series. That performance capped a brilliant postseason, and he was named World Series MVP.
But an injury-plagued Beckett went just 9-9 last year, and he began this season with a .500 career record (26-26) and a reputation as an underachiever.
"I've seen a tremendous change in the guy," manager Jack McKeon said. "I saw a great work ethic in spring training. I saw a guy that was focused and determined. He has all that potential, and he wants to bring it to the front, and he has been pitching like that."
Beckett walked one, struck out 11 and retired 14 consecutive batters before Jose Vidro doubled with one out in the ninth. The right-hander pitched six shutout innings to win on opening day.
"It's a basic formula I'm using this year -- control the things you can control, and don't worry about anything else," Beckett said. "Right after the last pitch of the game, you start thinking about your next one. If you don't, you'll go out and get shellacked, and I'm back to being a .500 pitcher again, and that's all anybody wants to talk about."
Pinch-hitter Paul Lo Duca broke a scoreless tie with a two-run double in the seventh. Florida added six runs in the eighth, capped by Encarnacion's third career slam. He also hit one in the Marlins' opener.
Beckett's performance lowered the Marlins' ERA to 1.07, and all three of their victories have been shutouts. They're just 3-3 despite outscoring opponents 31-9.
Until the seventh, Beckett was locked in a scoreless duel with John Patterson (0-1), who was given the start when Tony Armas Jr. went on the disabled list with a pulled groin.
Patterson retired 11 in a row before Carlos Delgado led off the seventh with a single, and Encarnacion walked. Lo Duca, who had been given the day off, came off the bench with two out and hit a liner into the opposite-field corner to score both runners.
"I hit it in the right spot," Lo Duca said. "In that situation you can't try to do too much."
Lo Duca came up inches short of a game-winning home run in the ninth inning of Florida's loss to Washington on Saturday.
Miguel Cabrera singled home a run in the eighth, and after Delgado was intentionally walked with runners at first and third, Mike Lowell also hit an RBI single. Encarnacion followed with his homer, which earned him a curtain call for the second time this week from a crowd of 25,089.
He also earned some ribbing from teammates.
"They said, `Leave some people on base for the other guys,"' he said.
Patterson was charged with two runs in seven innings.
"He couldn't do any more than he did," Nationals manager Frank Robinson said. "We just couldn't do anything with Mr. Beckett, so it didn't matter what John did."
Beckett threw 110 pitches, 78 for strikes. He frequently hit 95 mph on the scoreboard speed gun and retired the leadoff batter in every inning.
"He was spotting his fastball and throwing a nasty breaking pitch in the dirt, and guys were fishing," Matt Treanor said after catching Beckett for the first time since both were in Double-A. "He was throwing all three of his pitches and locating with all of them. You couldn't play Nintendo better."
- Florida's Juan Pierre was back in the lineup after his streak of 1,700 consecutive innings ended Saturday. He has played in 341 consecutive games.
- In the first week of the season, the Nationals hit two extra-inning homers. The Expos hit three all of last year.