That meant the right-hander was around to help out in the winning rally.
Omar Vizquel hit a two-run single and Pedro Feliz followed with a three-run homer as the Giants came from behind with two outs in the seventh inning to beat San Diego 6-2 and split a four-game series.
Morris singled and scored during the rally, which allowed him to win his fourth straight start. The Giants won for the fifth time in seven games.
"If I had had a lot of pitchers, I would have made the right move," manager Felipe Alou said, explaining why Morris batted with a man on and two outs in the seventh, with the Giants trailing 2-1.
"I know the bullpen had been used a lot," Morris said. "I told Felipe, 'I'll go as long as you want."'
San Diego's Chris Young (7-4) had his four-game winning streak end. He hadn't lost since May 24 against Atlanta.
Young retired the first two Giants batters in the seventh, then loaded the bases on singles by Eliezer Alfonzo and Morris, and Randy Winn walked after an 11-pitch at-bat. He fouled off five pitches with two strikes before drawing ball four.
Brian Sweeney relieved and allowed Vizquel's go-ahead, two-run single to right and Feliz's three-run shot to left, his 13th.
"We had great at-bats that inning," Alou said.
"Randy Winn had the at-bat of the game," Morris said.
Young threw 28 pitches in the seventh.
"Really the at-bat that killed us was Winn's," manager Bruce Bochy said. "He threw some great pitches and he kept fouling them off. He said that wore him out."
Young, though, said he never should have let Alfonzo and Morris reach base.
"That inning came down to the hitters before him," Young said. "Bad pitches on both guys and they made me pay, and we lost the ballgame because of it."
Sweeney was mad at himself for leaving a pitch over the plate for Feliz.
"I didn't execute my pitches," Sweeney said. "I'm very disappointed."
Feliz homered three times in the series. He also tripled in the go-ahead run in San Francisco 4-1 win Saturday night.
"A two-out rally is pretty good," Vizquel said. "Morris got a big hit and Randy Winn has an unbelievable at-bat. The whole inning was awesome."
Young allowed four runs and six hits in 6 2/3 innings, struck out seven and walked one. He gave up as many earned runs as he had in his previous six starts combined.
The 6-foot-10 right-hander, obtained in a six-player trade with Texas on Jan. 4, has been the most consistent member of the Padres' rotation. Even with Sunday's loss, his ERA during his last seven starts was just 1.59. His overall ERA is 3.13.
Morris (7-7) left begrudgingly after 7 1/3 innings. He allowed two runs and four hits, struck out six and walked three. His ERA in his last four starts was 1.48.
Steve Kline relieved Morris and loaded the bases before rookie Brian Wilson struck out pinch-hitter Rob Bowen and got Geoff Blum to fly out.
Wilson finished for his first career save in two chances.
Barry Bonds sat out Sunday after playing the first three games of the series, including both games of Saturday's split doubleheader.
The Padres took a 2-0 lead after two innings and could have scored more. They had the bases loaded with one out in the second before Eric Young grounded into a double play.
Josh Bard hit an RBI double in the first and Young had an RBI single in the second.
Morris settled down after that.
"I just started to get a better rhythm, a better feel," he said. "Down 2-0 at the start, Chris was throwing a great game. I knew I had to scrap back."
San Francisco's Ray Durham homered to right field leading off the fifth, his 10th. Durham also homered in the series opener Friday night, a 6-5 Padres win.
Padres manager Bruce Bochy said ace Jake Peavy will go to the back end of the rotation following the All-Star break in order to give him more time to rest his right shoulder. Peavy, whose start Wednesday at Philadelphia will be his last of the first half, has been bothered by tendinitis in his shoulder. ... Padres SS Khalil Greene sat out after getting hit by a pitch in the triceps Saturday night. ... LF Dave Roberts, on the DL with a bruised right knee, made a rehab appearance with Class A Lake Elsinore on Sunday and is scheduled to be activated when the Padres open a series at Philadelphia on Tuesday. ... Giants manager Felipe Alou needs one more victory for 1,000 in his career. He's 999-976 with the Expos and Giants.