KANSAS CITY, Mo. (AP) -- If the Chiefs keep this up, football will be fun again in Kansas City.
Desperate to proclaim an official end to one of the darkest periods in team history, the Chiefs hit San Diego with two long touchdown strikes and then stopped Philip Rivers in the shadow of the goal line four times in the final minute Monday night, preserving a 21-14 victory over the four-time AFC West champions.
"In rain and wind and really tough conditions, we were able to protect the football through the game," said second-year coach Todd Haley, whose Chiefs were routed by the Chargers twice last season. "I had that as No. 1 key for our offensive group. This is a big win for us. But it can't be too big."
Jamaal Charles of the Chiefs had a 56-yard touchdown run after Rivers' 3-yard TD pass to Antonio Gates put the Chargers on the board first. Then, rookie Dexter McCluster , a training camp sensation with quickness and flair, broke a team-record by one yard with a 94-yard punt return for a 21-7 halftime lead.
"That's the longest of my career at any level," said McCluster. "What better time than that - Monday night football in Arrowhead. You couldn't ask for a better time."
Rivers, who has had some of his finest days during a five-game winning streak over Kansas City, victimized a young secondary for several long gains. Legedu Naanee was all alone when he hauled in a 59-yard scoring pass to make it a one-touchdown game with 2:23 left.
Rivers then drove his team to a first-and-goal from the 4. His first pass was incomplete, then Darren Sproles lost 2 yards. Another pass sailed high. Then, with 39 seconds left, Rivers missed on fourth down and a rain-soaked crowd which hadn't seen the Chiefs win on Monday night in 10 years erupted in cheers.
A pounding rain began falling in the second quarter and it didn't taper off until the start of the fourth.
"They made some big plays in all three phases," Chargers coach Norv Turner said. "They handled the environment in terms of the weather conditions. I thought they did a good job in handling that, particularly in the second quarter.
"The disappointment for me comes obviously from our (kick) coverage teams. We think that should be a strength for us and something we work hard at."
With the goal-line stand and the two long touchdowns, the Chiefs turned the game into the confidence-building coming-out party they had been hoping for since the schedule was announced in April. The Chiefs brought an end to a three-year period that saw them win a total of 10 games and go through a front-office housecleaning that brought in Haley and general manager Scott Pioli.
It was also a rousing official unveiling of what they are calling "the New Arrowhead," a $375 makeover of the venerable stadium that seemed as loud as it had in the 1990s when Marty Schottenheimer's teams were going to the playoffs year after year.
"The fans tonight, what a great energy out there," Haley said. "And this is how I visualize Arrowhead and it's because of those people who were out there through some pretty difficult conditions. it didn't look like too many were shying away from it."
Rivers was 22 for 39 for 298 yards and two touchdowns. Cassel, with a history of playing poorly against the Chargers, was 10 for 22 for 68 yards, including a 2-yard TD pass following a San Diego turnover.
The 9:15 p.m. kickoff was the latest in Arrowhead history.
"This was the longest day of my life," joked Cassel.
Rivers found Antonio Gates for a 34-yard gain to set up his first touchdown, which was Gates' 12th career score against the Chiefs, his most against any opponent.
But as lightning flashed overhead, the Chiefs struck quickly to make up for an otherwise lackluster offense that totaled only 197 net yards.
After Kansas City's first two possessions produced nothing, Charles, a 1,000-yard rusher who was beaten out in training camp by veteran Thomas Jones , broke through a hole and sped 56 yards with 37 seconds left in the first quarter to tie the game.
Ryan Mathews , who is replacing perennial Pro Bowler LaDainian Tomlinson in the Chargers' backfield, took a brutal hit by Derrick Johnson and lost the ball. Brandon Carr scooped it up and ran 16 yards to the San Diego 12 and Cassel made it 14-7 with a 2-yard TD pass to rookie tight end Tony Moeaki .
Mathews, in his NFL debut, had 75 yards on 19 carries.
McCluster got the only block he needed from Andy Studebaker for his big punt return.
"You can't ask for a better platform, Monday night football in Arrowhead and getting a W," said McCluster, who was listed as doubtful on Saturday with an undisclosed illness. "What else can you ask for?"
NOTES: It was the Chiefs' first home Monday night game since Nov. 22, 2004, a 27-19 loss to New England. The Chiefs last won a Monday night game since Oct. 2, 2000, when they beat Seattle 24-17. ... The Royals beat Oakland 3-1 at Kauffman Stadium on Monday afternoon. The last time the Truman Sports Complex had two games on the same day was Oct. 27, 1985, when the Royals beat St. Louis in Game 7 of the World Series and the Chiefs lost to Denver that afternoon. ... In his past three games against Kansas City, Rivers had seven touchdown passes and no interceptions. ... The Chiefs had 197 yards total offense and 219 yards in punt and kickoff returns. ... Jones had 39 yards on 11 carries in his Chiefs debut.