Beckett struggled early but still pitched seven shutout innings Saturday as Florida beat the Rockies 4-1, extending their losing streak to 10 games.
After lasting just two innings in his previous start, Beckett (5-2) limited Colorado to five hits and one walk, lowering his ERA to 2.14.
"The first couple of innings his ball was all over the place," Florida catcher Paul Lo Duca said. "He didn't have his best stuff, but he got by. That's a great pitcher."
Colorado fell to 6-21, baseball's worst record and the worst start in franchise history. The Rockies, 1-15 on the road, are on pace to finish 36-126.
They did well to keep the latest loss close. Shawn Chacon (1-2) walked nine, allowed four hits and made a throwing error but held the Marlins to two runs in 5 2/3 innings.
"It's a good-kid, bad-kid thing," manager Clint Hurdle said. "You want to pat him on the back for battling, being gutsy and getting people out when he had to get them out. But he knows that for him to take the next step, his command has got to pick up."
Holliday tried to score from second on a two-out single in the second inning but failed to slide and was tagged out by Lo Duca, who took a one-hop throw from left fielder Miguel Cabrera.
"I was thinking about running over the catcher," Holliday said. "I got caught between running him over or sliding."
Holliday also allowed an unearned run to score when he dropped a short fly in left field in the seventh and then compounded his mistake by throwing to the wrong base, missing a forceout chance at second.
"I thought they would rule I caught it," he said.
Cabrera went 3-for-4 with a walk and drove in the first run. Florida won despite stranding 13 runners.
"We had many opportunities," manager Jack McKeon said. "We eked out enough runs. We got enough key hits when we needed them. Or sacrifice flies. Or errors."
Todd Jones pitched a perfect ninth for his second save in three chances.
Beckett bounced back from his lone loss this season, an 8-6 defeat last Sunday at Philadelphia.
"You think about it right up until game time, and then you've got to put it behind you," he said.
The right-hander improved to 4-0 at home with an ERA of 0.62, and he was helped by the Marlins' usual fine defense. Along with Cabrera's run-saving throw, shortstop Alex Gonzalez robbed Helton of a hit with a diving catch, and second baseman Luis Castillo made an acrobatic pivot on a double play.
"I don't know what I'm going to do if I end up playing for somebody else, I'm so used to them being behind me," Beckett said.
Chacon shut out the Marlins through four innings despite six walks, before they finally scored in the fifth.
Castillo singled and stole second, Delgado walked and Cabrera singled home a run. Juan Encarnacion walked, and Lo Duca hit a sacrifice fly.
With Juan Pierre at first base, the Rockies turned a weird 1-6-3 double play in the first. Castillo hit a liner off the glove of Chacon, who deflected the ball in the air to shortstop Barmes. He threw to first to double up Pierre. ... Rockies pitchers lead the major leagues with 145 walks. ... McKeon, who received an honorary degree of laws Saturday from Barry University, greeted reporters after the game in a lab coat. A sign over the door to his office read "Dr. McKeon."