SAN DIEGO (AP) — Freshman Ronnie Hillman scored on runs of 65 and 44 yards, finishing with 191 yards on 24 carries to lead San Diego State to a 27-25 upset of No. 23 Air Force on Saturday night.

Hillman broke his 44-yarder with two minutes left, on the first play from scrimmage after SDSU (4-2, 1-1 Mountain West) recovered an onside kick.

Air Force (5-2, 3-1) pulled to 20-18 on Nathan Walker's 4-yard run with 2:08 to go. SDSU defensive back Andrew Preston stopped Asher Clark at the 1-yard line on a two-point conversion. The conversion play originally was ruled a score, but was overturned after a lengthy review, with the officials ruling Clark's knee was down.

Air Force's Chaz Demerath caught a 7-yard touchdown pass from Tim Jefferson with 18 seconds left.

The Aztecs beat a ranked team for the first time since defeating No. 16 Wyoming 28-24 on Nov. 7, 1996. Since then, they'd lost 25 straight games to ranked opponents.

Air Force was knocked out of the top spot in the MWC. No. 4 Utah and No. 11 TCU are both 3-0 in league play.

SDSU's Ryan Lindley threw for 247 yards and one touchdown, with one interception.

Air Force came in leading the nation in rushing with 352.7 yards per game and finished with 312. A week earlier, SDSU allowed 271 rushing yards in a 24-21 loss at BYU.

It was Hillman's third game in triple digits this season. His best effort was 228 yards in a loss at Missouri.

Hillman's dazzling 65-yard run midway through the second quarter was the first score of the game. He took the handoff, broke one tackle, had a Falcons player miss a tackle and then jumped over a prone Air Force player to cruise into the end zone.

San Diego State took a 17-6 lead midway through the third quarter when wide-open tight end Gavin Escobar pulled in a high pass from Lindley with his left hand for an 8-yard TD.

Air Force answered with a scoring drive capped by tailback Clark taking a pitch along the right sideline, cutting inside and scoring on a 20-yard run. The Falcons botched the 2-point conversion attempt and trailed 17-12.

San Diego State made it 20-12 with a 27-yard field goal by Abel Perez early in the fourth quarter. Perez was wide left on a 19-yard attempt with 8:59 left.

Air Force got field goals of 25 and 30 yards from Erik Soderberg. His second field goal came after the Falcons kept the ball on a fair-catch interference call against SDSU that negated a fumble on a punt.

Copyright 2010 The Associated Press.