So much for the concerns about Johan Santana’s surgically repaired elbow. The New York Mets’ ace lefty showed on Opening Day that he was as good as new and that his poor performance in spring training was nothing more than an aberration.Santana allowed just one earned run in six innings, surrendering just four hits, striking out five and walking two, leading the Mets to a 7-1 win over the Florida Marlins at Citi Field Monday afternoon.It was the Mets’ fourth straight Opening Day victory and improved their overall Opening Day record to 31-17.Santana displayed his regular velocity and his tantalizing changeup in earning his first victory since last August. He had the Marlins off balance throughout the afternoon.Another Met who showed major signs of life was third baseman David Wright, who hit a two-run homer on his first at-bat of the season. Wright, who hit only 10 homers all season, took a Josh Johnson offering over the right field fence in Citi Field, giving the Mets a 2-0 lead that they would never relinquish.A host of newcomers had big days for the Mets. Gary Matthews, Jr., Rod Barajas and Jason Bay all had two hits in their Met debuts.Jeff Francoeur had two RBI for the Mets on a sacrifice fly and a run-scoring double.The Mets broke the game open with a four-run sixth inning. Barajas had an RBI double and Angel Pagan had a run-scoring pinch-hit single in the rally.Johnson, the Marlins starter and loser, surrendered four earned runs in five innings of work.Jorge Cantu drove in Florida’s lone run with a double. The Mets-Marlins series continues Wednesday at Citi Field.