Barry Zito waited a long time to finally pick up the fifth shutout of his career.

The left-hander will look to build off his outstanding 2012 debut this evening as San Francisco continues a three-game series with the Pittsburgh Pirates.

After being held to just 13 appearances and posting a 5.87 earned run average a season ago due to injury, Zito opened up the 2012 campaign with a four-hit shutout of the Rockies on Monday. He struck out four without a walk and faced the minimum in five of his nine innings, including the last two.

The 33-year-old left-hander, on the heels of a tough spring, made a start in the minors the previous week and said that went a long way toward helping him get back on track.

"I made the adjustment I had to make," he said.

It marked Zito's first shutout since April 19, 2003 against the Texas Rangers. He was pitching for the Oakland Athletics at the time and was coming off winning the AL Cy Young Award the previous year.

"He had four pitches going and great concentration out there," said Giants manager Bruce Bochy. "It wasn't a good spring, but it's been said many times -- spring training is overrated."

Zito has faced the Pirates five times in his career, going 1-3 with a 3.41 ERA.

While the Giants were certainly impressed with Zito's season debut, they were blown away with Matt Cain's second outing of the season. The right-hander took a perfect game into the sixth inning of last night's opener and struck out 11 in a one-hit shutout, leading San Francisco to a 5-0 victory in its home opener.

The only hit allowed by Cain was a two-out single slapped through the left side of the infield by Pirates starter James McDonald with two outs in the sixth. He picked up his fifth shutout and 14th complete game while leading the Giants to their third win in four games since an 0-3 start.

Cain (1-0) threw 73 of his 106 pitches for strikes and faced one batter over the minimum, picking up his first win since signing a six-year, $127.5 million contract extension earlier this month.

"He was getting ahead early, throwing the heck out of his changeup," said Pirates center fielder Andrew McCutchen. "I thought overall we were just chasing pitches out of the zone."

Giants catcher Buster Posey, in his first home game since suffering a broken leg and torn ligaments in a collision at home plate last May, knocked in the first run with a double to the center field wall in the first inning.

McDonald took the loss in the opener of the three-game series, giving up three runs on six hits and three walks in 5 2/3 innings.

Pittsburgh has lost four in a row to begin a nine-game road trip out west and is hitting just .178 on the season.

Tonight, the Pirates will get one of their biggest surprises of last season back in the mix with right-hander Charlie Morton slated to make his debut. He opened up the season on the 15-day disabled list while rehabbing from offseason surgery on his left hip.

Morton's future was in doubt after he logged just two wins and a 7.57 ERA in 17 starts in 2010, but the 28-year-old broke through with a career-best 3.83 ERA in 29 outings last season while posting a 10-10 record. He threw 98 pitches over 7 2/3 innings of a rehab start with Triple-A Indianapolis on Monday, allowing one run.

Morton went 1-0 with a 1.50 ERA in two starts versus the Giants last year and in his career against them is 2-3 with a 2.77 ERA in six starts.

These two clubs split their six meetings a season ago, with the Giants winning two of three at home. San Francisco has won nine of its past 12 at home versus Pittsburgh.