PITTSBURGH (AP) -- After needing the equivalent of three games merely to win twice in Pittsburgh, what a relief this regulation game was to the Chicago Cubs. Almost as big as the relief Jon Lieber gave them.
Geovany Soto and Mike Fontenot hit two-run homers in Chicago's five-run sixth inning and the Cubs finished off a three-game sweep of Pittsburgh, winning 7-3 on Thursday night to run their winning streak to five games.
Soto had three extra-base hits, including two doubles, among his second career four-hit game, and Derrek Lee also drove in two runs despite not getting a hit as the Cubs won their sixth in a row over the Pirates dating to last season.
Lieber (2-1) got the decision by pitching 4 1/3 scoreless relief innings after starter Rich Hill needed 72 pitches to get through three innings, allowing three runs and three hits and walking four. Lieber pitched 7 1/3 scoreless relief innings in the series, three of them during a 10-8, 12-inning win Monday in the Pirates' home opener.
"Without Lieber, we really would have had problems," manager Lou Piniella said. "We were looking for innings. ... [Hill] was all over the place. There was no use keeping him in there. It wasn't going to get any better."
The Cubs certainly didn't need to look for innings earlier in the series.
After going 12 and 15 innings to win the first two games -- the first time in 81 years they've needed that many innings to win consecutive road games -- the Cubs won this with one big inning against the pitching-thin Pirates, who dropped their fifth in six games.
"I'm glad it didn't go [extra innings]," said Soto, who went 8-of-17 while catching all 36 innings in the series -- apparently with no effect on his offense.
The Cubs withstood two Pirates homer-driven comebacks to win 6-4 in 15 innings on Wednesday night.
"I think any situation like that, if anybody can go in there and do that, it's definitely huge," Lieber, a converted starter, said of propping up the bullpen. "You want to give those guys a break down there, especially after last night's ballgame."
Soto had a chance to hit for the cycle, but he didn't think of trying to stretch a double into a triple in the seventh. He grounded out in the ninth.
"I already hit my one [triple] for the year. I'll take them if they come, but I don't want to get greedy," Soto said. "I'm not a triple-type guy."
After emptying their bullpen in consecutive games, the Pirates needed a lot of innings from starter Matt Morris (0-1), who lasted seven but gave up 11 hits and seven runs, four earned.
"I tried to avoid thinking about that all day -- the obvious thing is [to think], 'I've got to go eight, I've got to go nine, I've got to go seven, whatever it is,' and as soon as you start thinking like that, you can barely get out of the first," Morris said.
Morris led 3-2 going into the sixth but quickly fell behind when Kosuke Fukudome walked and Soto followed with a drive into the center field shrubbery for his second homer.
"I had the game in front of me but, all of a sudden, the home run just changed everything and it snowballed," Morris said.
Morris might have gotten out of the inning with only two runs scoring, but Ryan Theriot, who had singled, was safe at third on a steal attempt when third baseman Jose Bautista dropped Ronny Paulino's throw that arrived well ahead of the runner.
Theriot scored on Reed Johnson's single, and Fontenot made it 7-3 with a two-run, two-out drive into the right field seats, the third homer off Morris in two starts.
Xavier Nady and Bautista hit sacrifice flies in Pittsburgh's three-run first inning.
The Cubs scored at least six runs in every game of the series and have scored 35 runs in their last five games. ... Chicago's winning streak is its longest since winning seven in a row last June 22-29. ... The Cubs had as many extra-inning victories (two) in the series as they did last season, when they were 2-8 when playing more than nine innings. ... Until this series, Chicago hadn't won back-to-back road games of more than 12 innings since 1927, when they beat Boston in 18 innings (May 14) and 22 innings (May 17). ... Soto also had a four-hit game against the Cardinals on Sept. 16. ... Morris has lost six of his last seven decisions against the Cubs and seven of his last nine after starting his career 10-2 against them.