SAN DIEGO -- The moment of truth had arrived. Jake Peavy lives for moments of truth.

It was the top of the sixth inning Monday at Petco Park. San Francisco Giants slugger Barry Bonds, the reason that the eyes of the baseball world fell on San Diego on Opening Day, was at the plate with a runner on second and one out. The Padres held a one-run lead.

With a base open and the best hitter of his generation -- any generation? -- up, logic screamed at Peavy to walk Bonds, who had ripped a ground-rule double off the Padres' ace in the second inning. But Peavy isn't always logical.

When Darren Balsley visited the mound, Peavy told his pitching coach, "I want to pitch to him and get him out."

Peavy did just that, inducing a fly out to center field. In the bottom of the inning, Khalil Greene belted a two-run home run and the Padres were off and running toward an impressive 6-1 victory over the Giants before a sellout crowd of 43,767.

Peavy and the Padres shut out San Francisco after the second inning, Mike Piazza hit an opposite-field homer in his first Padres at-bat, and Greene drove in three runs as the defending National League West champions began their quest to repeat in style.

"It's hard to put together a better ballgame than what we did tonight," Padres manager Bruce Bochy said.

Said Peavy: "We have a long way to go, but we wanted to show people what kind of baseball we're capable of playing. I think we're a more well-rounded team."

In his first Opening Day assignment, Peavy pitched as if he were releasing pent-up frustration from being denied a Petco start in the World Baseball Classic. Throwing mostly hard fastballs, he allowed one run on only four hits in seven innings. He retired 15 of the last 17 batters he faced and struck out the side in the seventh, with Mike Matheny whiffing on Peavy's 96th and final pitch.

"He's unbelievable," said Piazza, who caught Peavy for the first time in a game that mattered. "He has great stuff and he's competitive. He's definitely a throwback guy."

Peavy could have been forgiven if he had been gun-shy versus Bonds, who claimed the 24-year-old right-hander as the victim of his 700th career homer two years ago and nearly went deep against him in the second inning. Instead, Peavy attacked during the game's crucial at-bat.

With Omar Vizquel on second base and Moises Alou on deck in the sixth inning of a 2-1 game, Piazza called for a fastball low and outside. Peavy spotted it perfectly. Bonds flied out harmlessly to Dave Roberts, who played center for the injured Mike Cameron.

"I felt confident in my ability to make that pitch," Peavy said.

Said Piazza: "Barry's a special player, but when you come after him, it sets the tone. In certain situations, you do have to challenge the best hitters in the game."

Piazza's a pretty darn good hitter himself, and he showed the Padres that he still has plenty of power in his 37-year-old body. After San Francisco took a 1-0 lead in the top of the second on Lance Niekro's single to drive in Bonds, Piazza drove a one-ball pitch from Giants right-hander Jason Schmidt over the scoreboard in right-center field, 389 feet away.

"I guess this park isn't too big for him," said Bochy, making light of the frequent gripes since Petco opened about the difficulty of hitting the ball out, particularly to right-center. "That shows you how strong he is."

Piazza became the ninth Padre to homer in his first at-bat, and his 398th career homer tied him with Dale Murphy for 43rd on the all-time list.

"It's a big ballpark, but (Schmidt) took a little off the pitch over the plate, and I got some extension," said Piazza, whose best power is to the opposite field. "If that ball doesn't go out, I might think about hanging them up."

The Padres surged ahead in the fifth inning when Josh Barfield led off with a single -- his first major-league hit -- and later scored on Eric Young's sacrifice fly. Greene's two-run shot into the second deck in left field in the sixth extended the lead to 4-1. Two more runs in the eighth prevented Bochy from having to use closer Trevor Hoffman.

"We played a great game," said first baseman Adrian Gonzalez, who had two hits and scored twice. "We were all hoping for a game like this."

Contact staff writer Brian Hiro at b_hiro@hotmail.com.