NFL-Chiefs rout mistake prone Texans for Wild Card win

* Hoyer throws four interceptions * Chiefs return opening kickoff for touchdown * Watt injured and does not return (Adds details, quotes) Jan 9 (Reuters) - The Kansas City Chiefs used a dominating defense and workmanlike offence to crush the mistake prone Houston Texans 30-0 on Saturday as the National Football League postseason opened with a dreary rout. The Chiefs, who stormed into the postseason on a 10-game winning streak, got the AFC Wild Card contest off to an explosive start when Knile Davis returned the opening kickoff 106 yards for a touchdown to send a jolt through the capacity crowd at Houston's NRG Stadium. The second longest kickoff return in NFL playoff history would stand up as the only touchdown of the first half with Brazilian kicker Cairo Santos adding two second-quarter 49-yard field goals. "You never expect to start a game like that," said Chiefs quarterback Alex Smith. "But we feel like we can play three phases of football and special teams really came out today and gave us a kick start." The AFC South champion Texans were fortunate to escape an error-riddled opening half trailing just 13-0 after turning the ball over four times. Brian Hoyer's first postseason appearance was not a memorable one as the Houston quarterback fumbled once and tossed three interceptions in a miserable opening half, including one with the Texans poised to score on the two-yard line. Kansas City pushed the Texans into an even bigger hole when Smith marched the Chiefs 94 yards on their opening possession of the second half, hitting Chris Conley with a nine-yard touchdown strike to cap the drive. There was more bad news for the Texans in the third quarter when team leader J.J. Watt, the NFL's reigning defensive player of the year, left the field with an apparent leg injury and did not return. Texans fans were headed to the exits after Spencer Ware scampered for another touchdown on the first play of the fourth quarter that capped another long drive and put the Chiefs out in front 27-0 before Santos closed out the scoring with his third field goal of the game. Smith, taken by the San Francisco 49ers with the number one overall pick in the 2005 draft, was not spectacular but was his usual efficient self, completing 17-of-22 passes for 190 yards, a touchdown and his first interception in four playoff contests. "There were a lot of unknowns, it's been a long time since the last time we played them and we were just trying to see how they would treat some of our formations and I think we got that ironed out at halftime," said Smith, explaining why it took a half for the Chiefs' attack to get in gear. "We've got high character guys who have put in the time and sacrifice." Hoyer's final stats made for horrific reading as he completed just 15-of-34 passes for 136 yards and was picked off four times. (Reporting by Steve Keating in Toronto. Editing by Larry Fine.)