Kansas City, Mo. ? After three straight victories, the Kansas City Chiefs have to be careful not to pout about what might have been.

“What might have been was the 13-3 (record of) last year,” fullback Tony Richards said. “But the thing that matters most is we’re starting to come into our own.”

Taking advantage of numerous Denver mistakes, the Chiefs (6-8) romped to a 45-17 victory Sunday.

The Broncos, who have lost three of their last four, committed 100 yards in penalties. They also let Jake Plummer get sacked six times and generally looked nothing like playoff contenders.

“This game was not a fun game,” said Plummer, whose two interceptions both led to Kansas City touchdowns. “It was a bad day.”

Larry Johnson and Eddie Kennison each scored two touchdowns, and Dante Hall returned the opening kickoff 97 yards for another score for the Chiefs, who all but dropped out of playoff contention with a four-game losing streak in November.

The Chiefs scored on four of their first five possessions en route to their biggest margin of victory in the long series since a 31-point victory in 1983.

“It was a Kansas City Chief day,” coach Dick Vermeil said. “We had a lot of things go our way.”

Kansas City’s third and sixth touchdowns came off Dexter McCleon’s interceptions of Plummer, who was fined $5,000 last week for making an obscene gesture to a fan in Denver.

Kansas City wide receiver Eddie Kennison (87) celebrates his 18-yard touchdown reception as Denver's Champ Bailey (24) and Nick Ferguson walk off the field during the fourth quarter. The Chiefs won, 45-17, Sunday in Kansas City, Mo.

“We were trying too hard,” Denver safety John Lynch said. “We had missed assignments and fell apart.”

Plummer has eight interceptions and only one touchdown pass in his last three games. He was 23-for-41 for 292 yards.

“This team does not give up,” Plummer said. “We will not give up. We should be producing more.”

Typical of Denver’s day was a fourth-quarter play when Tatum Bell took a screen pass and went 58 yards before Greg Wesley punched the ball out of his hands at the five. The ball went into the end zone and out of bounds, making it a touchback and giving Kansas City possession on the 20.

“We’re going to have to do something about that,” said Denver coach Mike Shanahan. “He gets the ball inside the five-yard line, and somebody shoots him from the stands.”

Johnson, the second-year running back who spent most of the year in Vermeil’s doghouse, had 151 yards on 30 carries, including touchdown runs of five and 32 yards. Finally getting a chance to showcase his skills, the former first-round draft pick has gone over 100 yards in each of his last three games and scored five TDs.

Kansas City cornerback Dexter McCleon (22) pulls down Denver Broncos wide receiver Triandos Luke (10) after Luke caught a pass for a nine-yard gain in the first quarter.

Trent Green completed 16 of 19 passes for 224 yards and three touchdowns. He had touchdown tosses of seven and 18 yards to Kennison, who beat standout cornerback Champ Bailey each time.

Kennison’s second TD capped a 10-play, 99-yard drive that included penalties against Bailey for illegal use of hands and Al Wilson for roughing the passer.

Rookie Samie Parker, making his first start, got behind the Denver defense for a 48-yard catch-and-run in the third period that put Kansas City on top 35-10.

It took Hall just 13 seconds to put the Chiefs on top. Taking the opening kickoff on the three, he went right, cut left and found a clear path down the left side, going the distance virtually untouched for his second kickoff return TD of the year.

Kansas City running back Larry Johnson (27) goes for a short gain as Chiefs tackle Jordan Black (65) blocks Denver defensive end Reggie Hayward. Johnson had 151 yards in the Chiefs' 45-17 victory Sunday in Kansas City, Mo.

“I think you should go talk to (the blockers) because all I had to do was run,” Hall said. “I didn’t even get touched.”

Plummer threw the ball right to McCleon in the second period and the Chiefs corner returned it 22 yards. Six plays later, Kennison beat Bailey in the end zone for a seven-yard TD catch and a 21-7 lead.

“I just missed my man,” said Plummer. “It is something that can’t happen. But it did.”

Johnson made it 28-7 when he appeared to catch the Denver secondary out of position and went through a big hole up the middle for his 32-yard TD.

Plummer hit Rod Smith on a 22-yard touchdown pass in the first quarter and Jason Elam’s 27-yard field goal cut the lead to 28-10 with 4 seconds left in the half.

Notes: In his first extensive action, Parker caught three passes for 84 yards for the Chiefs. … Reuben Droughns started at running back for Denver but had only four carries for 27 yards, giving way to Bell, who had nine for 50. … Johnson’s 151 yards against the Broncos matched the total recorded by the Chiefs’ Priest Holmes in the season opener at Denver. Holmes is out for the season with strained knee ligaments. … According to the Elias Sports Bureau, the Chiefs are the first team in NFL history with three different backs going over 150 yards in a game in one season. In addition to the big games by Johnson and Holmes against Denver, Derrick Blaylock rushed for 186 against New Orleans.