Backup quarterbacks Case Keenum and Taylor Heinicke led third-quarter touchdown drives to lift the Minnesota Vikings to a 17-10 victory over the Buffalo Bills in the preseason opener for both teams on Thursday night in Orchard Park, N.Y.

The Vikings improved to 13-1 in preseason games under coach Mike Zimmer, while the Bills didn't do much to impress in new coach Sean McDermott's preseason debut.

Keenum completed 11 of 16 passes for 121 yards and engineered a 69-yard touchdown drive in the opening minutes of the second half. C.J. Ham's 2-yard run gave the Vikings the lead for good.

Heinicke hit rookie Rodney Adams on rollout for a 2-yard touchdown that capped a 71-yard drive and gave Minnesota a two-touchdown lead with 1:14 left in the third quarter.

Buffalo's rookie quarterback, Nathan Peterman, completed 13 of 25 attempts for 112 yards and tossed a 1-yard touchdown to Dez Lewis to make it 17-10 with 10:16 left in the fourth quarter.

The Bills had a chance to tie the game after a Joe Powell interception in Vikings territory but failed on fourth down at the 17 with eight minutes remaining.

Each team produced only a field goal in the first half. Buffalo took the lead early in the second quarter on a 42-yard kick by Stephen Hauschka and the Vikings answered with a 36-yarder from Kai Forbath at 3:26 of the second quarter.

The Bills' first-team offense netted 79 yards on three drives. Jonathan Williams started in place of star tailback LeSean McCoy (rest) and rushed for 39 yards on four carries. Tyrod Taylor was 5 of 8 passing for 46 yards. Taylor connected with Sammy Watkins on Buffalo's first three plays. Watkins finished with 39 yards on four catches.

Minnesota's offensive starters also played three series, but managed only one first down. Sam Bradford completed 5 of 7 passes for 35 yards and was sacked twice. Rookie running back Dalvin Cook rushed for 13 yards on five carries and caught four passes for 30 yards.

The Vikings were already without projected starting running back Latavius Murray (ankle) and backup Jerick McKinnon (lower leg) when Bishop Sankey injured his knee in the third quarter and had to be helped off the field. Starting cornerback Trae Waynes (shoulder) left the game after one series and did not return.