Mahomes scrambled for a 27-yard touchdown run with 11 seconds left in the first half.
After the game, he told reporters he had briefly considered running out of bounds before remembering the Chiefs' timeout situation:
In the Titans' defense, Mahomes only ran for 218 yards during the regular season. They couldn't have expected the reigning MVP to beat them with his feet en route to finishing as Kansas City's leading rusher (53 yards).
Mahomes had another ruthlessly efficient game through the air, going 23-of-35 for 294 yards and three touchdowns.
This was the second week in a row the Chiefs scored a touchdown in the final minute of the first half to cap off a comeback, though Sunday's revival required far less work than the one in the divisional round.
After scoring 28 points to erase a 24-point deficit to the Houston Texans, clawing back from a 17-7 hole probably felt like nothing against Tennessee. Now, the Chiefs are one victory away from their second Super Bowl title.
With the San Francisco 49ers coasting early against the Green Bay Packers, Super Bowl LIV is shaping up to be a matchup between the NFL's most dynamic aerial attack and most dominant secondary.