Jamaal Charles' 56-yard touchdown run and Dexter McCluster's team-record 94-yard punt return gave Kansas City a two-touchdown lead and the Chiefs held San Diego on four downs inside the 6-yard line in the final minute for a 21-14 victory Monday night.

Playing most of the game in a pounding rain, the Chiefs turned it into the confidence-building coming-out party they had been hoping for since the schedule came out in April. By beating the four-time defending AFC West champions, they proclaimed an end to a three-year period that was one of the darkest in team history.

Philip Rivers thoroughly outplayed Chiefs quarterback Matt Cassel and drove the Chargers to a first-and-goal from the 4. But a pass was incomplete, Darren Sproles lost 2 yards and another pass sailed high. Then with 39 seconds left, Rivers missed again.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

KANSAS CITY, Mo. (AP) — Legedu Naanee caught a 59-yard touchdown pass from Philip Rivers with 2:23 left in the third quarter and the San Diego Chargers pulled within 21-14 of the Kansas City Chiefs entering the final period Monday night.

Naanee was wide open, 20 yards behind a young Chiefs secondary, and scored untouched.

Chiefs defensive end Tyson Jackson left with a knee injury right before the touchdown.

The Chiefs had scored 21 straight points, two touchdowns coming on big plays, to take a 21-7 lead.

Rookie Dexter McCluster returned a punt a team-record 94 yards for a touchdown and Jamaal Charles ran 56 yards for a touchdown as the Chiefs took the 21-7 halftime lead.

The Chargers had won five straight over the Chiefs, including 37-7 and 43-14 routs last season.

The Chiefs passing game was almost non-existent with Matt Cassel completing 8 of 17 for 48 yards in the first three quarters, although one was a 2-yard touchdown to Tony Moeaki with 5:55 left in the second quarter. That was set up by Brandon Carr's fumble recovery and return to the San Diego 12.

McCluster's punt return with 1:43 left in the half broke Dante Hall's record of 93 yards set on Oct. 5, 2003, against Denver.

Javier Arenas, another Chiefs rookie, returned punts 36 and 24 yards in the second quarter to give Kansas City good field position, but the offense failed to take advantage.

Charles' 56-yard touchdown run with 37 seconds left in the first quarter made it 7-7 after the Chiefs failed to make a first down on their first two possessions.

Rivers gave the Chargers a 7-0 lead with a 3-yard touchdown pass to Antonio Gates with 1: 52 left in the first quarter. A wide-open Gates made a 34-yard reception on third down and was stopped at the 5 to set up the touchdown.

It was the first regular season game since Arrowhead Stadium underwent a $375 million renovation. It was the Chiefs' first home Monday night game since Nov. 22, 2004, a 27-19 loss to the New England Patriots. The Chiefs have not won a Monday night game since Oct. 2, 2000, when they beat Seattle 24-17.

The last time the Truman Sports Complex had two games on the same day was Oct. 27, 1985, when the Kansas City Royals beat the St. Louis Cardinals in Game 7 of the World Series and the Chiefs lost to Denver that afternoon. The Royals lost 3-1 to the Oakland Athletics on Monday afternoon at Kauffman Stadium, across the parking lot from Arrowhead.