NEW YORK (AP) -- Edinson Volquez was much more effective against international competition.
Making his third consecutive opening day start, Volquez never got an out in the fourth inning and the San Diego Padres were routed by the New York Mets 11-2 on Monday.
Jonathon Niese stepped nicely into his new role as No. 1 starter for the Mets, and Collin Cowgill's grand slam capped a splashy New York debut during a season opener that quickly turned into a colossal flop for the Padres.
"We got beat pretty solid on both sides," manager Bud Black said. "We didn't pitch well at all. Like I said all spring, you've got to pitch well and we just didn't today."
Handed the opening day assignment in place of injured Johan Santana, Niese (1-0) enjoyed a big afternoon with both his arm and bat. He breezed into the seventh inning against a San Diego lineup missing slugger Chase Headley (broken thumb) and catcher Yasmani Grandal, suspended for the first 50 games after testing positive for testosterone.
The fast-working lefty gave up Carlos Quentin's run-scoring single and Yonder Alonso's solo homer before walking off to a standing ovation with two outs in the seventh.
"He was moving the ball around. He was throwing his cutters and curveballs for strikes," Alonso said. "He kept everybody off balance and got ahead of guys. ... So we just have to be a little more aggressive."
Niese also had a perfect day at the plate, tying his career high with two hits. He slapped an RBI single in the second off Volquez (0-1), then drew a leadoff walk and scored in a three-run fourth.
Volquez helped the Dominican Republic win the World Baseball Classic last month. But he gave up six runs, six hits and three walks in three-plus innings at windy Citi Field while falling to 0-5 in six starts against the Mets.
"I was off a little bit," Volquez said. "I got behind in the count and they hit the ball pretty good."
Touted prospect Jedd Gyorko made his major league debut for the Padres with about 30 family members and friends in the stands. He stranded four runners in his first two at-bats, then grounded a double inside third base for his first hit in the sixth.
"It was a good feeling," Gyorko said. "Niese kind of had my number. I was swinging at a lot of his curveballs, and he left one up. I don't know if he was getting tired or one just got away from him."
The ball was tossed into the San Diego dugout to be saved as a souvenir for Gyorko.
"I'm going to keep it until my mom steals it," he said.
Marlon Byrd had a pair of RBI singles and fellow Mets newcomer John Buck was in the middle of three rallies as New York improved baseball's best opening day record to 34-18 (.654) despite dropping its first eight openers.
The Mets have won 20 of their last 22 season openers at home.
New York scored nine runs with two outs and went 7 for 14 with runners in scoring position after batting .246 in those situations last season, 20th in the majors. The three new additions to the lineup -- Cowgill, Byrd and Buck -- were a combined 6 for 14 with seven RBIs and five runs.
"So far, so good," a smiling David Wright said. "It was good to kind of bust out offensively and get some breathing room for Jon."
With the Yankees hosting the rival Boston Red Sox at the same time across town, the Mets announced a sellout crowd of 41,053 at Citi Field, where the Padres won the ballpark's first game in 2009. The last time two New York teams opened at home on the same day was April 17, 1956, when it was the New York Giants and Brooklyn Dodgers, according to STATS.
Byrd and Buck each had an RBI single in the third. Cowgill doubled to key the fourth-inning rally, which included a run-scoring groundout by Wright and an RBI single by Daniel Murphy.
By then, Anthony Bass had replaced Volquez.
"He just couldn't make pitches at critical times," Black said. "Got through the first inning, got an out with a runner in scoring position, then 27 pitches in the second, 28 in the third, just missing on all his pitches."
Cowgill, batting leadoff after winning the center field job this spring, hit his first career slam off Brad Bach in the seventh to make it 11-2.
NOTES: Padres pitching prospect Casey Kelly, a key piece in the trade that sent Adrian Gonzalez to Boston in December 2010, is scheduled for Tommy John surgery Tuesday on his right elbow. It will be performed by Dr. James Andrews. ... Headley, the NL RBIs leader last year with 115, is expected to miss at least the first two weeks of the season. ... Gyorko started at second base and moved to third in a double switch. ... Cody Ransom started at 3B after injuries landed Headley, Logan Forsythe and James Darnell on the 15-day DL. Ransom made an error and struck out twice before he was removed in a double switch.