Dontrelle Willis gave the Cubs glimpses of his knees, elbows and glove. But the rookie left-hander with the unorthodox delivery didn't give the Cubs any runs over 5 2/3 innings Tuesday at Wrigley Field.

Then came a 1-hour 24-minute rain delay chasing 33,227 fans for shelter. As the skies darkened, so did the Cubs' hopes of reeling in the Florida Marlins, who held on to win 4-3 as Sammy Sosa popped out to third to end the game with two men on base.

"We've been battling back. We just came up short," Cubs manager Dusty Baker said.

"I think the guy [Willis] showed enough in six innings to convince you that he isn't too bad," said Florida manager Jack McKeon, whose Marlins had lost their previous five games to the Cubs.

After the rain delay, Nate Bump (2-0) entered in relief of Willis with runners on the corners and two outs in the sixth. Trenidad Hubbard was hit by a pitch to load the bases. But Juan Pierre ran down Damian Miller's deep drive to right-center.

Cubs starter Carlos Zambrano also blanked the Marlins for six innings, allowing seven hits, striking out four and walking three. He gave way to Mike Remlinger after the rain delay and the left-hander promptly surrendered back-to-back homers to Luis Castillo and Pudge Rodriguez.

"Usually good pitches don't go out of the yard. So, no, they weren't good pitches," said Remlinger (5-3), who was saddled with the loss.

Antonio Alfonseca replaced Remlinger and yielded an RBI single to Pierre in the eighth to make it 3-0. Rodriguez, who has 25 hits in his last 57 at-bats, drove in another run with a single in the eighth to chase Alfonseca.

Willis, selected by the Cubs in the eighth round of the 2000 amateur draft, threw 106 pitches, 67 for strikes. He allowed only three hits, struck out six, walked two and hit a batter.

"For me it's all about timing," Willis said. "If I get the timing back and good direction to the plate, then anything's possible. At first I was a little off because of the mound dimensions and stuff like that, but you have to battle. Go out there and still get it done."

Willis (8-1) picked up National League pitcher and rookie of the month honors for June after going 5-0 with a 1.04 ERA in five starts. But Baker left him off the NL roster for the All-Star Game.

Baker, however, said Willis would be next in line if an injury or other circumstances happened to a player on the team.

"It is what it is," Willis said. "You take it with a grain of salt, hope you have some longevity in this game and hopefully I'll get to be up there next year or the year after."

The Cubs finally got on the board in the eighth when Sosa hit his 14th home run of the season and the 513th of his career to pass Ernie Banks and Eddie Mathews on the all-time list. Sosa has 484 homers as a Cub, leaving him 28 behind Banks.

The Cubs rallied in the ninth when Ramon Martinez opened with a walk off reliever Braden Looper. Miller doubled before Tom Goodwin grounded out to score Martinez. Mark Grudzielanek singled to score Miller to make it 4-3 and pinch-hitter Lenny Harris walked, putting runners on first and second.

Moises Alou then lined out to second as Harris hustled back to first to avoid being doubled off.

Sosa hit an infield popup to end the game. Looper said the only good pitches he threw in the ninth were against Sosa.

"Oh, yeah. I'm the lucky one," Sosa said.