The San Diego Chargers are sitting alone atop the AFC West, but don’t believe they’re playing their best football.

The Kansas City Chiefs feel like they’re finally starting to come around after an embarrassing start, but they haven’t really been tested lately.

The Chargers look to bounce back from a disappointing loss Monday night when they visit the Chiefs, who are trying to win their fourth in a row and claim a share of first place in the division.

San Diego (4-2), which had its run of division titles end at four as Kansas City captured the crown last season, was in position to extend its winning streak to four last Sunday, leading the New York Jets 21-10 at halftime. The Chargers failed to score after the break, however, and quarterback Philip Rivers threw two fourth-quarter interceptions that led to the Jets’ last 10 points in a 27-21 road loss.

“We just need to play better and put a complete game together,” said Rivers, who finished with a season-low 179 passing yards.

“We still haven’t put one together and we’re 4-2. You can look at that two ways: Obviously, we’re not playing as good as we can and we’ve won four games or we better put it together or we’re not going to get done what we want to get done.”

Rivers has clearly not been playing up to his potential.

The three-time Pro Bowler has seven touchdown passes to nine interceptions — four fewer than he had all of last season. He had no touchdowns and two interceptions in a 20-17 win over Kansas City on Sept. 25, a victory that started the Chargers’ three-game winning streak.

That loss was the Chiefs’ third straight to start the season, but they’ve rebounded by winning their last three. No team has started 0-3 and won its next four games since Pittsburgh in 2000.

Kansas City’s wins haven’t come against the NFL’s top competition, however. The Chiefs (3-3) have defeated last-place teams Minnesota and Indianapolis and beat an Oakland squad last Sunday that was unsettled at quarterback.

They intercepted both Kyle Boller and Carson Palmer three times in a 28-0 victory. It was the franchise’s first six-interception game since 1984 against Seattle and first road shutout since beating San Diego in 1973.

“The great part about what this team has done is we just continue to grind and take it one game at a time,” Chiefs quarterback Matt Cassel said. “You can see us get better from the start of the season until now.

“Hopefully, we’ll just continue to make progress. We know it’s a one-game season every week.”

Cassel had two interceptions against the Raiders — his first picks since throwing one to Eric Weddle at midfield with 55 seconds left in San Diego last month.

In that meeting, the Chiefs were playing their first game since all-pro running back Jamaal Charles was put on injured reserve with a torn left ACL. Kansas City’s ground game was in flux and finished with a season-low 81 yards. It has since found some consistency behind Jackie Battle and is averaging 145.3 rushing yards during the winning streak.

Battle, who has run for 195 yards on 35 attempts in the last two games, will be facing a San Diego defence that has yielded 162 rushing yards in each of its last two contests.

Kansas City’s defence has also been susceptible against the run, ranking 25th in the league with 125.5 yards allowed per game. The Chargers’ Ryan Mathews rushed for 98 yards and two touchdowns on 21 carries in last month’s matchup.

The Chiefs, 8-2 at home since the start of last season, have lost seven of eight to the Chargers, with the lone victory coming in a Monday night game at Arrowhead Stadium to open last season.

“We just have to keep believing,” Kansas City cornerback Brandon Flowers said. “We never bowed our head and thought the season was done like some people did.

“We just knew if we kept pushing, things would turn around for us. It’s going to be a great showdown.”