Upset is a bolt from the blue for Philip Rivers, Chargers Philip Rivers hadn't even reached the airport after Sunday's game in Kansas City, and already his spirits had climbed to 35,000 feet. The San Diego quarterback said he was calling from the team bus, although it sounded closer to cloud nine. "This is one of those games you'll never forget," the elated cellphone Charger said as teammates hollered and laughed in the background, basking in the afterglow of a 41-38 upset of the Chiefs. Rivers clinched the victory with a 26-yard touchdown pass to receiver Seyi Ajirotutu with 24 seconds to play, not only halting San Diego's losing streak at three games but also keeping flickering playoff hopes alive. "We're not fooling ourselves about what we have to do, but we needed this," said Rivers, whose team is among five at 5-6 and realistically in the hunt for the AFC's sixth playoff spot. Before the game, we just said, 'Let's put our heads down and work for a full 60 minutes, then look up at the scoreboard and see what happens.' For head-swiveling observers, it was more like a tennis match. There were eight lead changes, the most in an NFL game since 2011. The Chiefs, who hadn't lost at home this season, appeared to have clinched the victory when Alex Smith found Dwayne Bowe with a five-yard touchdown pass with 1 minute 22 seconds remaining at Arrowhead Stadium. But Rivers and the Chargers weren't done. They answered with a seven-play, 78-yard drive that took 58 seconds and included a 12-yard catch by Antonio Gates on third and 10, receptions of 19 and 14 yards by Danny Woodhead, and the surgically precise touchdown pass to the double-covered Ajirotutu, who caught the ball as he fell to the ground. As he came to the line of scrimmage, Rivers alerted Ajirotutu to run a fly pattern if the Chiefs had two deep safeties and would give him an unimpeded release up the sideline. Ajirotutu saw what he needed to see and bolted upfield. "Philip said, 'Fly on the boundary,'" said the fourth-year receiver, undrafted from Fresno State, who made his first touchdown catch since 2010. So I knew that's a little code word that he usually says that the ball's coming to you. The Chiefs, who had been the NFL's last undefeated team, dropped to 9-2 after consecutive AFC West losses to Denver and San Diego. It was a big setback to the defense Sunday that they lost the league's top pass-rushing tandem, Tamba Hali and Justin Houston, to injuries in the second quarter. Hali suffered a sprained right ankle, and Houston followed with a sprained left elbow. Both will undergo MRI exams Monday. The Chiefs, who had a league-leading 35 sacks through the first eight games, had failed to get to the quarterback for the better part of the last three games, until safety Eric Berry sacked Rivers late in the fourth quarter. That diminished pass rush applied extra pressure on the secondary, and a defense that hadn't given up more than 17 points in any home game. It surrendered that many to the Chargers in the fourth quarter. "I'm not making excuses," Kansas City Coach Andy Reid said when asked about the injuries to Hali and Houston. The next guy has to come in, and we expect them to step up and make plays. There's no excuses. There's no respite for the Chiefs, who Sunday face the Broncos for the second time in three weeks, this time at Arrowhead. The Chargers don't have an easy stretch run, either, although four of their final five games are at home. They play host to Cincinnati and the New York Giants before a road game at Denver, and finish with home games against Oakland and Kansas City. Rivers said Sunday was "kind of what our season's been about - can you drive and score at the end? It's the kind of win that can save a season. On this day, seared into their memories, the Chargers answered that call. Half-hearted defeats OK, let's get this straight. The Indianapolis Colts have played all four NFC West teams. They beat Seattle and San Francisco - two of the NFL's elite - then, in the last three weeks, are blown out by St. Louis and Arizona?