New Mexico (6-6, 4-2) rallied from a 19-0 second-quarter deficit with a pair of TD's, closing to within 22-14 late in the third quarter, but the Lobos couldn't overcome failures on fourth down in the second half. CSU, headed to the Liberty Bowl on Dec. 31, prevailed despite being outgained 307-252.
"We did the things that win football games,'' coach Sonny Lubick said. "We won the special teams battle. We were huge on fourth down defensively, and we forced a couple of turnovers.
"There are only a few teams with 10 victories out there right now. That says a lot.''
Sapp, who did not start, finished with 36 yards on 14 carries. With 1,338 yards on the season, he remains within reach of the school single-season rushing record of 1,419, set by Steve Bartalo in 1986.
"He wasn't running like the Cecil of old,'' Lubick said, "but the one thing about Cecil is you can always depend on him protecting the football.''
New Mexico coach Rocky Long, whose team could have tied Colorado State for first place in the conference with a victory, said, "Aside from the turnovers, our team played like this was a title game.
"We didn't win the field-position battle, and we made too many mistakes. We turned the ball over too much.''
After a safety and field goal, Colorado State increased its lead to 12-0 late in the opening period. Jeff Babcock's 23-yard field goal made it 5-0, before Lobos freshman tailback DonTrell Moore fumbled when he was hit by linebacker Adam Wade. Rams Linebacker Drew Wood recovered at the New Mexico 26.
Quarterback Bradlee Van Pelt, who rushed for 106 yards, capped a six-play scoring drive with a 3-yard run, putting Colorado State ahead 12-0 late in the opening period.
Midway through the second quarter, Moore fumbled again at the end of a 12-yard run when hit by safety David Vickers. Wade picked it up and ran 9 yards before lateraling to Nelson, who went the final 54 yards for a 63-yard touchdown return and a 19-0 lead.
Asked why he pitched the ball back to Nelson, Wade said, "I got caught last year against Wyoming twice on the 1-yard line. I wasn't going to get caught again. He (Nelson) told me to pitch it. I didn't realize at the time how big the play was going to be.''
New Mexico responded with a 16-play, 78-yard drive that consumed 7:15 and ended with backup quarterback Justin Millea's 1-yard run. The drive included a 15-yard pass-interference penalty against the Rams and Casey Kelly's 10-yard pass to Dwight Counter on fourth-and-6.
Babcock's 46-yard field goal put the Rams ahead 22-7 midway through the third quarter.
Moore, who finished with 181 yards rushing, carried five times on a six-yard drive, including his 12-yard scoring run, to cut the deficit to 22-14 late in the period.
Moore, who was stopped for no gain on fourth-and-1 at the Colorado State 41 by Bryan Save early in the third period, was dumped again for no gain on a fourth-and-10 pass play with 3:11 left by linebacker Drew Wood and defensive end Peter Hogan.
Three plays later, Van Pelt's TD's run clinched it.
The Rams led 19-7 at halftime despite being outgained 167-98.
Just minutes into the game, Joey Huber's 60-yard punt pinned New Mexico at its 10-yard line, and Tyler Gaus' ensuing punt was blocked by David Anderson through the end zone for a safety.