Mets starting pitcher Steven Matz delivers a pitch against the...

Mets starting pitcher Steven Matz delivers a pitch against the Cincinnati Reds during the first inning of a game at Citi Field on Sunday, June 28, 2015. Credit: Kathleen Malone-Van Dyke

The Mets welcomed Stony Brook's Steven Matz as the sixth starter in their pitching rotation, but as well as he pitched Sunday, the more interesting question might be whether he should be third or fourth in their batting order.

Matz not only won a 7-2 decision over the Reds in his major-league debut but drove in four runs with a 3-for-3 day at the plate for one of baseball's most anemic lineups.

On the pitching side, manager Terry Collins said Matz came "as advertised." He allowed five hits in 7 2/3 innings and two runs on solo homers by Brandon Phillips and Todd Frazier, walking three and striking out six.

The lefty, a 2009 second-round draft pick out of Ward Melville High School, showed remarkable composure in shaking off the homers by Phillips, the first big-league hitter he faced, and Frazier, striking out both the next time he faced them.

But Matz and Collins agreed the biggest moment came at the plate in his first at-bat.

With Darrell Ceciliani on third and two outs, Reds rookie starter Josh Smith (0-1) intentionally walked Eric Campbell.

Big mistake. Matz was hitting .304 for Triple-A Las Vegas (7- for-23), and he proved it was no mirage by lining a two-run double to deepest center for a 2-1 lead.

"We needed a big hit no matter where it came from," Collins said. " . . . That hit kind of lifted everybody in the dugout."

Matz, who borrowed a bat from Las Vegas 51s infielder Matt Reynolds, enjoyed the sight of the ball sailing over the glove of speedy Reds centerfielder Billy Hamilton. "I barreled it up, and it felt good off the bat," Matz said. "I saw it go over his glove. It was pretty cool."

Nothing fazed Matz. Not the delay to complete Saturday's suspended game that pushed back his first pitch to 4:38 p.m., not the homers he gave up nor the magnitude of the moment as he made his debut in front of a crowd of 29,635 that included upward of 130 family members and friends.

"He pitched great," Collins said. "He wasn't intimidated by anything. The home run that Frazier hit, you could tell he didn't make the pitch he wanted to make in the location he wanted. He was pretty upset, but he settled down and got the next guy out. You can't let something that just happened affect your next pitch, and he never did that, not one time the entire game."

But it was at the plate where Matz's uber-competitive nature was most on display.

Campbell walked to lead off the fifth. After showing bunt while working the count to 3-and-1, Matz belted a single through the left side. Curtis Granderson's double then drove in Campbell for a 3-2 lead.

In the sixth, Matz came up with the bases loaded and none out as many fans stood and cheered in anticipation. He lined a 2-and-2 pitch just over the glove of a leaping Phillips at second for a two-run single and a 5-2 lead.

Six innings into his Mets career, Matz was in the team record book as the first player at any position to have four RBIs in his MLB debut, and he tied team records for hits in a game (three) and RBIs in a game (four) by a pitcher. Matz became the 11th player in the last 100 years with three hits and four RBIs in his MLB debut, and he was the only one of those 11 to go 3-for-3.

Asked if his debut lived up to his dreams, Matz said, "It definitely matched it. Your whole body was tingly out there with the crowd and how big the stadium is. It was really cool."