Fort Lauderdale, Fla. (AP) -- One yellow and green sign summed it up best: USF, the only Undefeated School in Florida.
Then again, the lofty ranking was nearly short-lived.
South Florida (5-0) committed four turnovers for the second straight game and gave FAU two chances to muster a game-winning drive. But Williams and Grothe did enough to overcome the mistakes.
"For us to win this game with all those turnovers is remarkable," USF coach Jim Leavitt said.
Williams had a 9-yard scoring run to break a 7-7 tie in the third quarter. Grothe made it 21-14 with a spinning, juking, tackle-breaking 32-yard run two possessions later.
Williams' third TD run was even better. He spun out of one tackle, broke two more and scampered 54 yards to make it 28-17 with about 10 minutes remaining.
"I just got out there and ran the ball every time they gave it to me," Williams said. "I just want to be consistent."
Florida Atlantic (3-3), playing its home games about 15 miles from campus at Lockhart Stadium, was more consistent throughout the game and didn't quit against its first top-10 opponent.
FAU forced two punts in the closing minutes, but couldn't sustain a final drive. Williams' 9-yard score with 29 seconds remaining sealed the victory after FAU failed to convert on fourth down.
"It's a bittersweet defeat because we didn't take advantage of all the opportunities we had to win the game," FAU coach Howard Schnellenberger said. "The sweet part of it is that we played them as well as anybody has this season."
South Florida may have expected a letdown after its 21-13 victory over then-No. 5 West Virginia eight days ago. But few could have seen a near meltdown coming.
Schnellenberger may have been one of them, especially after spending the last seven years building his FAU program in the mold of Leavitt's team, which has been around 11 seasons.
The latest win for South Florida, though, came with two key injuries.
Defensive end George Selvie, who entered the game leading the nation in sacks, had one on the first series. It gave him 10 1/2 on the season, breaking the single-season school record. He was injured a short time later and played sparingly the rest of the way.
"I'm a little banged up, but I'll be OK after some rehab," Selvie said.
Running back Jamar Taylor sprained his left ankle early and did not return.
Williams and Grothe picked up the slack.
Williams' yardage, touchdowns and 25 carries all were career highs. He ran 19 times for 162 yards in the second half. Grothe carried 14 times, and completed 17 of 27 passes for 122 yards with an interception.
Smith was 23-of-47 passing for 259 yards for FAU. He had three TD passes and an interception.
"We did a lot of good things, but it's hard to claim a moral victory when you had a chance to win the game," Smith said.
The Owls had several chances to build a big lead in the first half. But they missed three field goals and whiffed on what seemed like a sure sack.
Grothe escaped two defenders on third-and-9, rolled right and found Amari Jackson for a 29-yard gain. The Bulls scored two plays later on Williams' 6-yard TD run, taking a 7-0 lead late in the first quarter.
The Bulls had three turnovers in the opening half, and FAU turned one of them into points. The Owls missed field goals after the other two.
Warley Leroy was wide left from 36, 42 and 45 yards in all.
"I don't think we came out flat," Grothe said. "A few early turnovers got us down and it took a while to get back up."