Not seeing much pressure, Luck threw touchdown passes of 28 yards to Reggie Wayne and 18 to T.Y. Hilton in leading the Colts to 17 points. Adam Vinatieri added a 52-yard field goal as Indianapolis scored on three consecutive series.
Backup kicker Brandon McManus added a 50-yard field goal in the second half.
New York's Josh Brown kicked field goals of 25, 27 and 45 yards in the first half.
Luck, who led the Colts to an 11-5 record in his rookie season, completed 9 of 13 passes, but the one most will remember will be the gift touchdown courtesy of Giants cornerback Aaron Ross. On a second-and-3 play from the 28, Luck underthrew Wayne on a pattern down the right sideline. A backpedalling Ross was in perfect position to intercept the ball, but he lost his balance, had the ball slip out of his hands and then hit his leg and pop up into the air. Wayne came down with it in the end zone for a 7-3 lead.
NFL this week
Pittsburgh at Washington, 6 p.m., ESPN
New England at Detroit, 5:30 p.m.
Carolina at Baltimore, 6 p.m.
Seattle at Green Bay, 6 p.m.
Chicago at Oakland, 8 p.m.
Buffalo at Washington, 2:30 p.m.
Cleveland at Indianapolis, 5 p.m.
N.Y. Jets at N.Y. Giants, 5 p.m.
Kansas City at Pittsburgh, 5:30 p.m.
Philadelphia at Jacksonville, 5:30 p.m.
Tampa Bay at Miami, 5:30 p.m.
St. Louis at Denver, 6 p.m.
Cincinnati at Dallas, 6 p.m.
Atlanta at Tennessee, 6 p.m.
San Diego at Arizona, 8 p.m.
Sunday, Aug. 25
New Orleans at Houston, 2 p.m.
Minnesota at San Francisco, 6 p.m.