SAN FRANCISCO (AP) -- After waiting a while for his first major league homer, patience finally paid off for Julio Zuleta of the Chicago Cubs.

Zuleta tied the game in the eighth with his first big league homer and Jose Nieves' sacrifice fly in the 11th inning gave the Chicago Cubs a 3-2 victory Saturday over the San Francisco Giants, just the Cubs' eighth win in 24 road games this season.

After being held scoreless on one hit for the first 7 2/3 innings, the Cubs tied the game at 2 on back-to-back homers by Henry Rodriguez and Zuleta off reliever John Johnstone.

Rodriguez's 12th homer of the season went into the seats above the brick wall in right-center. Zuleta's homer, capping a 12-pitch at-bat, went to left field.

"He kept swinging at fastballs and staying alive, staying alive," Johnstone said. "I came back with a slider and he hit it."

Zuleta spent seven years in the minors before finally reaching the majors this season, and has gotten some playing time recently at first base while Mark Grace is on the disabled list.

"I was real happy because I've been waiting for a long time to get this opportunity," said Zuleta, who struck out in his first three at-bats against Russ Ortiz. "I was fighting in that at-bat to get a good pitch to hit. That's very hard when you don't play a lot of games, your timing is off a little."

Rodriguez opened the 11th with a double off Aaron Fultz (1-1). Pinch-runner Chad Meyers moved to third on a groundout and, after a walk, scored on Nieves' fly to right.

Daniel Garibay (1-1) pitched two hitless innings for his first major league win. Rick Aguilera pitched the 11th for his eighth save in 12 opportunities.

The two homers in the eighth deprived Ortiz of a win after a roller-coaster performance in which he allowed one hit in six scoreless innings -- striking out a career-high 11 and matching his career high with seven walks.

"The first six to seven innings we were really not patient," Rodriguez said. "We were lucky they took (Ortiz) out of the game, and we took advantage of that."

Ortiz allowed only a double by Willie Greene in the fifth. He struck out the side in the fourth and fifth innings, got Sammy Sosa twice on strikes and whiffed Zuleta swinging three times.

"He picked a bunch of young guys that kept chasing that fastball out of the strike zone," Cubs manager Don Baylor said. "They were balls, they were out of the strike zone. When you have young guys, it looks like a good pitch to hit."

Ortiz walked two in the first and walked three straight batters with two outs in the third. But he retired Rodriguez on strikes to end the threat in the first, and got Rodriguez to line to right with the bases loaded in the third.

In the fifth inning, after a one-out walk to Eric Young and Greene's double put two runners in scoring position, Ortiz struck out Sosa and Jeff Reed.

"The only time I worry about walks is when I give up a hit after them. The walks didn't hurt today, they didn't cause a run," Ortiz said. "I'm going to walk people. That's the kind of pitcher I am at this point."

Jeff Kent and Ellis Burks had RBI singles in the first for the Giants, who opened the series with a 5-3 win over the Cubs on Friday night.

Scott Downs allowed two runs on seven hits in six innings for the Cubs, who broke a five-game losing streak in San Francisco.

"It hurts big time," Giants manager Dusty Baker said. "We had some opportunities to tack on some more runs. It just didn't happen for us."

Game notes
Ortiz has allowed three or more walks in 42 of his 56 career starts. ... The Cubs have had back-to-back homers six times this season. ... Johnston had his third blown save of the season. ... The 11 strikeouts by Ortiz were the most by a Giants pitcher since Shawn Estes also had 11 on June 15, 1998, against Colorado. ... The Giants are 3-11 in one-run games this season.