College football's Week 2 slate delivered two of the season's biggest shocks so far, with unranked Baylor and South Florida both toppling ranked opponents in games decided in the final seconds.

Baylor beat No. 17 SMU 48-45 in double overtime, capping the comeback with a walk-off field goal in a back-and-forth shootout that saw the lead change hands repeatedly down the stretch, according to Covers.com's roundup of the week's biggest upsets. The win snapped SMU's hopes of an early-season signature victory and instead handed the Bears one of their own.

USF's Second Straight Ranked Scalp

South Florida topped the drama with an 18-16 win over No. 13 Florida, also decided on a walk-off field goal, per NCAA.com's live coverage of Week 2. It's the second straight week the Bulls have knocked off a ranked team — they opened the season by blowing out then-No. 25 Boise State 34-7 — instantly turning South Florida into one of the sport's early feel-good stories and putting the rest of the American Athletic Conference on notice.

SOUTH FLORIDA HAS NOW BEATEN TWO RANKED TEAMS IN AS MANY WEEKS

The upsets weren't confined to the Power Four ranks. Three FCS programs knocked off FBS opponents in Week 1 alone, according to a separate NCAA.com report, extending a season-opening trend of chalk getting thrown out the window across the sport. For Baylor and South Florida, both programs still building toward respectability after uneven recent seasons, the wins offer an early signal that this year's non-conference schedule could scramble the national picture well before conference play even begins.