Floyd had been away from the team for nine days dealing with the death of his father, then found his rhythm in a hurry.
Floyd hit a go-ahead two-run single in the ninth inning, when the Cubs rallied against Tim Lincecum for a 5-1 victory over the San Francisco Giants on Tuesday night, to remain tied for the lead in the NL Central.
"I can't really explain, except it felt like he was inside me," Floyd said of his late father, Cornelius, who died of a stroke. "I've never felt that before. Coming back and helping the team my first game is a great feeling. Usually I get a little anxious. For some reason today I felt really calm."
Lincecum (7-4) was three outs from his first career complete game when the Cubs finally got to the rookie right-hander. Ryan Theriot doubled to start the ninth, Jacque Jones followed with a base hit before Derrek Lee's RBI single tied the game at 1.
Two batters later, Floyd singled off Brad Hennessey to put Chicago up 3-1.
"Floyd gets a big hit," Piniella said. "Cliff had to really feel good about that. I'm happy for him. It should lift his spirits. I told him before the game, 'Cliff, we need you."'
Scott Eyre (1-1) pitched the eighth for the win against his old team. Jason Kendall added a two-run single later in the ninth off Steve Kline for the Cubs. Chicago began its six-game West Coast trip with a hard-fought win and stayed even with the Brewers, who won 7-4 at Arizona.
"It's a big win, what can I say?" Piniella said. "We did our part."
Lincecum, like Floyd, had been on the bereavement list. He came off a four-day stint away from his team and dazzled for most of the night. Lincecum had allowed only a pair of singles before Lee's hit ended his night in frustrating fashion -- though he still left to a standing ovation.
"We were eight-ninths not in business," Piniella said. "That ninth-ninth we were. That's the one that counts. It takes one-ninth."
Not only did the defeat cost Lincecum a victory, the last-place Giants saw their longest winning streak since an eight-game run from April 18-26 end at five.
Ryan Klesko's RBI groundout in the first put San Francisco ahead, then Lincecum did his job. He struck out seven and walked one in a 93-pitch performance. Still emotional after a death in his family, Lincecum opted not to talk about his outing after the game.
Barry Bonds, who has a record 760 home runs, returned to the lineup after two days off. He went 0-for-3 with a strikeout and his 37th intentional walk, his 122nd overall.
"Come on, Lou!" one man yelled at Piniella when Bonds was walked in the first inning.
Kendall, the Cubs' No. 8 hitter, reached base twice against Lincecum, with a single to start the sixth and a two-out walk in the eighth. Mark DeRosa singled in the second.
Lincecum had thrown only 43 pitches through four innings, 32 for strikes -- making quite an impression in only his 20th big league start. He had a no-decision at Wrigley Field on July 16 in his only other matchup with the Cubs.
"We had a lead in the ninth and what a game our kid was pitching," Giants manager Bruce Bochy said. "They got the hits, though. What a way to lose a game. He pitched great. He just got some balls up in the ninth and they took advantage. We might have been a little hyped up there -- it was his first situation in the ninth up here."
Floyd had been 0-for-3 before his clutch hit in the ninth.
Cubs starter Jason Marquis had won his last two starts, but this time the right-hander went seven innings -- the first time he'd gone longer than 6 2/3 innings since beating Arizona on July 20. He struck out five and walked five, two intentional, allowing three hits and one run.
Eyre told Marquis the victory was all his.
"I got a vulture win," Eyre said. "The way Timmy was pitching, it was kind of fun to watch."
Omar Vizquel hit his second triple of the season in the seventh.
- Dave Roberts stole his 25th base in the seventh. His steals are the most by a Giant since Marvin Benard had 27 in 1999.
- To make room for Lincecum, the Giants placed RHP Russ Ortiz on the DL for the third time this year. He has a torn tendon in his elbow that likely will sideline him the rest of the season and it might require surgery.
- The Cubs have scheduled their makeup game of Sunday's postponed home contest with the St. Louis Cardinals for Sept. 10 at Wrigley Field.
- The Giants drew 41,242 fans for their 36th sellout and 20th in a row.