Denver Broncos quarterback Peyton Manning acknowledges the crowd after breaking the single-season touchdown record during an NFL football game against the Houston Texans, Sunday, Dec. 22, 2013, in Houston. Denver Broncos coach John Fox, left, celebrates with Peyton Manning (18) after Manning threw a touchdown pass during the fourth quarter of an NFL football game against the Houston Texans, Sunday, Dec. 22, 2013, in Houston. Houston Texans defender Kareem Jackson (25) breaks up a pass intended for Denver Broncos' Demaryius Thomas (88) during the second quarter of an NFL football game on Sunday, Dec. 22, 2013, in Houston. Houston Texans' Matt Schaub looks to pass against the Denver Broncos during the third quarter of an NFL football game on Sunday, Dec. 22, 2013, in Houston. HOUSTON (AP) - Peyton Manning never dreamed he'd throw an NFL record 51 touchdowns just two years removed from neck surgeries that threatened to end his career. Manning reflected on his remarkable comeback soon after regaining the NFL record for touchdown passes in a season in Denver's 37-13 win over the Houston Texans on Sunday that gave the Broncos their third straight AFC West title. "There was major unpredictability," Manning said. So a lot of (doctors) said: 'Maybe you'll come back to this level and maybe not.' So there was definitely some wait and see ... but no, it would be hard to say you could have imagined this at that point. He missed the entire 2011 season after four neck surgeries weakened his right triceps and put his future in question. Now 37, Manning regained his record when he threw for 400 yards and four touchdowns, including three in the fourth quarter. He surpassed the 50 TD passes Tom Brady threw in 2007 and led the Broncos (12-3) to the victory over the Texans (2-13) that extended Houston's franchise-record skid to 13 games. Just 2½ minutes earlier, he tied the mark with a 20-yard pass to Eric Decker. "It's just amazing to be able to be a part of it," Denver center Manny Ramirez said. Everything we see from Peyton, being prepared, it's worked for him. "It's never fun to be on the opposite end of a record-breaking performance," Houston defensive end J.J. Watt said. The guy is a heck of a football player and you give credit where credit is due. There is a reason the guy should be MVP this year. Five things to know about the Broncos-Texans game: ANDRE'S RECORD: Houston receiver Andre Johnson finished with four catches for 63 yards. Johnson entered the game needing one catch to reach the mark held by Denver's Wes Welker. Johnson also had more than 100 receptions in 2006, 2008, 2009 and 2012. "It's all fine and dandy," Johnson said of the record, "but I only play the game for one reason, and that's to win. It's a great thing to happen, but under these circumstances it really doesn't matter. NO WELKER, NO PROBLEM: Welker missed his second straight game after sustaining his second concussion in four weeks on Dec. 8. But Manning still had a big day thanks to the strong play of Denver's other receivers. Julius Thomas added six receptions for 78 yards. Demaryius Thomas leads the team with 1,317 yards receiving, Decker has a career-high 1,261 and Julius Thomas 752, also a career-best. Matt Schaub started for the first time since Oct. 13 in place of the injured Case Keenum. He finished with 176 yards and one touchdown with two interceptions. Schaub, benched for Keenum after a terrible six games, admitted that he has thought about the possibility Sunday was his last game for Houston. "It has definitely crossed my mind," he said. I didn't want to think too far ahead, but I've played this game long enough to know how things work. MILLER'S KNEE: The Broncos lost star linebacker Von Miller to a knee injury in the first quarter. Miller was able to walk off the field on his own after being hurt in the first quarter. Miller was the second overall pick in the 2011 draft and won Defensive Rookie of the Year honors. He was suspended for the first six games this season after violating the league's drug-abuse policy. He has started all nine games since his return and has five sacks. Denver coach John Fox didn't have an update on Miller's condition after the game. "They'll have tests," Fox said. Anything until we get all of the tests will be purely speculation, so we will just wait until we hear something definitive. KNOWSHON 1K: Denver's Knowshon Moreno had 11 carries for 76 yards on Sunday to reach 1,015 yards for his first career 1,000-yard rushing season and the 20th in franchise history. He also had two receptions for 26 yards to give him 507 yards receiving and make him the first player in Denver history to have 1,000 yards rushing and 500 yards receiving in a season.