STILLWATER, Okla. — When Troy defeated Oklahoma State in 2007, Cowboys quarterback Zac Robinson was making his first collegiate start and often looked like a deer in headlights.

One year later, the junior was poised and deadly accurate, completing 13 of his first 14 passes, three for touchdowns, in leading OSU (4-0) to a big early lead at Boone Pickens Stadium en route to a 55-24 victory over the Trojans (2-2). A stadium record crowd of 52,463 mostly orange-clad Cowboys faithful were on hand for the game.

Robinson threw for 213 yards in the first half, with six of the completions, three for touchdowns, going to sophomore Dez Bryant, who closed the first half with 118 receiving yards. The duo helped OSU pile up 612 yards of total offense.

OSU’s 355 yards of total offense in the first half was more than the Troy defense had allowed in any of its last five games, going back to the Western Kentucky game in 2007.

For the second straight week, the Trojans allowed their opponents to march down the field for a touchdown on the opening possession of the game. Oklahoma State needed 11 plays to cover 67 yards, with the final 16 coming on a pass from Robinson to Bryant with 9:44 left in the opening quarter.

The Cowboys took advantage of a Trojan turnover to push their lead to 14-0 late in the first quarter. After a Hampton pass over the middle was deflected and intercepted, OSU drove 54 yards in nine plays for its second score of the game.

Sophomore Kendall Hunter ran in from four yards out for the touchdown with 29 seconds left in the half.

Another Troy turnover, this one a fumble by Jerrel Jernigan, led to another OSU score. The Cowboys took over at their own 26 and needed just nine plays to drive 74 yards, ending in a 26-yard scoring strike from Robinson to Bryant with 7:28 to go in the half.

The Trojans finally put together a complete drive and cut the OSU lead to 21-7 with 5:12 left in the half on a five-yard pass from Hampton to Austin Silvoy. The big plays in the drive included a career-long 38-yard run from Jernigan, a 12-yard pass from Hampton to Harris and a 13-yard run by Harris. The 73-yard drive used just 2:16 off the game clock.

OSU answered right back with a quick scoring drive of its own. Robinson connected with Bryant for their third touchdown of the game, this one covering 44 yards as the 6-foot-2 sophomore out-jumped Troy corner Trevor Ford for the ball at the five and walked into the end zone with 2:45 left in the half.

Troy answered again, driving 50 yards in 12 plays before stalling and settling for a 47-yard field goal from Sam Glusman with 51 seconds left in the half.

A short kickoff and solid return gave OSU possession bear midfield, and the Cowboys again took advantage. A 20-yard gain on a shuffle pass moved the ball to the Troy 37. An 18-yard pass to Damian Davis moved the ball to the Troy 17, and Hunter took it the rest of the way on a draw, pushing the OSU lead to 35-10 with 20 seconds left in the half.

After Troy failed to pick up a first down on its opening possession of the second half, freshman Will Goggans punted the Cowboys back to their own one. OSU went right to work on the ground, using 11 plays, all rushes, to cover 99 yards for a touchdown. Junior Keith Toston covered the final yard, and 29 yards on four carries on the drive, but it was Hunter who got 64 of the yards, 41 of which came on one carry.

Troy answered with an 11-play drive of its own, covering 80 yards. Hampton’s second TD pass of the game covered 12 yards to Jernigan with 5:49 left in the third, cutting the OSU lead to 42-17.

OSU added a field goal late in the third quarter, capping another 11-play drive, to push its lead to 45-17.

Troy completed a 10-play scoring drive of its own early in the fourth quarter when Hampton hitting senior Fred Turner in the corner of the end zone from 15 yards away at the 14:29 mark. It was Turner’s first career touchdown, and cut the OSU lead to 45-24.

The Cowboys put the game away after converting a fake punt on a fourth and 11 from deep in their own territory. OSU took the momentum from that play and scored 13 plays later on a 19-yard field goal from Bailey for he 48-24 lead.

On Troy’s first play on the next possession, Hampton’s pass was intercepted by Jeremiah Price and returned 19 yards to the Trojan 20-yard line. Toston punched it in from 16 yards out and with Bailey’s PAT, the Cowboys increased their lead to 55-24.

The Trojans will return to action a week from Tuesday at Florida Atlantic in a game that will be televised nationally on ESPN2.