The 250-pound back had four touchdown runs and New England kept Andrew Luck from a second consecutive comeback victory to beat the Indianapolis Colts, 43-22, Saturday night.
Blount scored on three two-yard runs in the first half, then burst through the right side of the line and rambled 73 yards into the end zone, where he put the ball gently on the ground made soggy by a game-long rain. He had 166 yards in 24 carries.
On the next series, Luck threw his third interception and the Patriots capitalized with Stevan Ridley's second touchdown run, this one from one yard that finished the scoring with 11 minutes 12 seconds left.
The Patriots will face the winner of the game Sunday between the Denver Broncos and San Diego Chargers.
Blount joined Ricky Watters, who had five touchdowns for San Francisco on Jan. 15, 1994, as the only players with four or more in a playoff game. And the six rushing touchdowns by the Patriots tied the 49ers' total in that game for second most in playoff history.
Blount's big rushing performance came two weeks after he ran for 189 yards and returned two kickoffs for 145 yards in the Patriots' 34-20 victory over Buffalo in the regular-season finale.
Luck threw an interception on his second pass and never found consistency. He threw two touchdown passes to LaVon Brazill but also had four passes intercepted.
The Colts trailed, 21-12, after the first half and cut it to 29-22 on a 35-yard pass to Brazill with 5:01 left in the third quarter. The Patriots dominated the rest of the way.
Blount's first touchdown came on New England's first offensive play after Alfonzo Dennard intercepted Luck's pass and returned it 27 yards to the two.
Blount scored again on the Patriots' second series in which Tom Brady completed all four of his passes.
But Luck responded with a seven-play, 80-yard drive capped by his 38-yard touchdown pass to Brazill, who was guarded closely by Dennard as he made the catch on the left side a few yards from the end zone.
Former Patriot Adam Vinatieri set an NFL record with his 59th postseason extra point, making it 14-7.
Blount got his third touchdown with 4:06 gone in the second quarter on a drive in which the Patriots converted all four of their third downs.
Vinatieri's 21-yard field goal early in the third quarter made it 21-15.
Then the Patriots took a 29-15 lead on Ridley's three-yard touchdown run and his carry for a two-point conversion with 6:18 to go in the third quarter.