Kansas City, Mo. ? Neither 12 years in the league nor nine trips to the Pro Bowl could prepare left tackle Willie Roaf for what he did, saw and felt on this history-making day.

Shredding what had been the NFL’s leading defense against the run, Priest Holmes and Derrick Blaylock each scored four touchdowns rushing Sunday in a stunning 56-10 rout of Atlanta (5-2). The eight TDs on the ground set an NFL record.

Down 3-0 in the opening minutes, the Chiefs (2-4) roared back with a 35-0 blitz and totaled 271 yards rushing against an embarrassed defense that had led the league with an average yield of only 74.5 yards on the ground.

“To go out and break an NFL record against a 5-1 football team is just unbelievable,” Roaf said. “It’s incredible. That’s a good football team, and they’ll bounce back. This was a college-type football game today. I’m just glad I was a part of it.”

Holmes scored on runs of 1, 2, 2 and 15 yards in the first half. He was stopped just a couple of feet short of what would have been his fifth TD rushing for the Chiefs (2-4).

The man who set the NFL record last year with 27 touchdowns rushing then left because of a mild ankle sprain.

But all Holmes’ injury did was unleash backup Blaylock against the helpless Atlanta defense.

Blaylock, who had a 7-yard TD in the first half, immediately scored on a 1-yard run after Holmes was hurt. He added TD runs of 3 yards, then 2 yards in a game that also saw the Chiefs record a team-record 36 first downs.

Much of the yardage was behind Roaf and left guard Brian Waters.

Kansas City running back Priest Holmes (31) leaps into the end zone over Atlanta defenders Matt Stewart and Siddeeq Shabazz (26) in the second quarter. Holmes and Derrick Blaylock each rushed for four touchdowns Sunday in the Chiefs' 56-10 rout of the Falcons at Arrowhead Stadium in Kansas City, Mo.

“They had, like, the No. 1 rushing defense,” Blaylock said. “But once we started moving the ball on them, we just kept moving the ball. We got in a rhythm. And eight touchdowns later, we’ve got the record.”

Holmes totaled 139 yards on 22 carries and Blaylock had 90 on 19. Altogether, the Chiefs amassed 540 yards in handing the Falcons their second-most lopsided loss.

“We didn’t have an answer for anything they did,” Atlanta linebacker Keith Brooking said. “There is no worse feeling as a linebacker than having the ball rammed down your throat. We were the No. 1 rushing defense and they hammered us.”

Holmes’ four TDs rushing in a half tied the NFL record and also broke the record for most in a game against the Falcons.

“I am honored to be a part of history,” Atlanta coach Jim Mora said sarcastically. “We have done a tremendous job of stopping the run. So it just emphasized how well they played. Their O-line was doing such an excellent, tremendous job, it might not have mattered who was in there.”

The Chiefs’ historic day began, oddly enough, with Holmes losing a fumble on their first play from scrimmage.

Kansas City's Derrick Blaylock (23) is tackled by Atlanta linebacker Demorrio Williams.

“In a game like that, you just want to keep running the ball,” Waters said. “For an offensive lineman, that’s a lovely day. That’s a dream.”

The collapse of the defense, which had been given great credit for Atlanta’s 5-1 start, nearly was complete. The defense came in with 20 sacks but hardly even got a hand on Trent Green, who had 269 yards passing on 20 completions.

“The red light started going off,” Atlanta tackle Ed Jasper said. “They were literally the best running team we’ve played against. They took it to us.”

It was Holmes’ eighth game with three or more touchdowns as a Chief.

“I’m excited because it sets this offensive line apart from any offensive line in history,” Holmes said. “They created lanes and seams and we did an excellent job as far as reading them.”

Michael Vick’s 32-yard run set up Jay Feely’s 19-yard field goal on Atlanta’s first possession, then the Chiefs reeled off five straight touchdowns and stunned the visitors with a 35-3 halftime lead.

The same Atlanta defense that last week held San Diego’s LaDainian Tomlinson to 64 yards on 23 carries was gouged for 140 yards in the first half. Offensively, the Falcons converted only one of 11 third-down attempts.

Kansas City's Jared Allen, right, sacks Atlanta quarterback Michael Vick in the fourth quarter. The Chiefs beat the Falcons, 56-10, Sunday in Kansas City, Mo.

“They just out-executed us,” said Vick. “We couldn’t get anything going.”

Vick rushed for 62 yards on six carries, including 32 yards on his first drive, and was replaced in the fourth quarter by Matt Schaub.

The Falcons got their only touchdown when Allen Rossum returned a punt 75 yards in the third period.

Notes: The Falcons’ most lopsided loss was 59-0 to the Los Angeles Rams on Dec. 4, 1976. That also was the day they gave up seven TDs rushing. … The Chiefs’ 540 total yards is the seventh-highest in team history. Their three points was the fewest allowed by the defense since a 31-3 win over Chicago in December.