INDIANAPOLIS —Whew.

After holding their collective breath as Houston Texans kicker Kris Brown lined up for a potential game-tying 42-yard field goal, the Indianapolis Colts could breathe a sigh of relief after that kick sailed just left up the uprights to preserve a 20-17 victory Sunday.

“We did the things we planned to do, which was go up-tempo,” Colts coach Jim Caldwell said. “It was almost like our two-minute operations to take over the game. We wanted to press the issue and be as expressive as we possibly could.”

Caldwell knew that this ride wouldn’t be easy. Not with three defensive starters, including 2007 NFL Defensive Player of the Year Bob Sanders, ruled out for the season this week. Not as the lone unbeaten squad remaining in the AFC. And certainly not facing an upstart Texans squad with designs on challenging the Colts for the AFC South title.

Knowing that a quick start offensively would give his defense a boost, Colts quarterback Peyton Manning put his offense into hyperspeed in the first quarter. In all, Manning went 19-of-25 for 176 yards — decent stats for a game for most quarterbacks, just another day at the office for the Colts’ signal caller — in the opening 15 minutes.

Those 176 yards included a 7-yard touchdown pass to Joseph Addai with 6 minutes, 20 seconds gone by in the contest. Those yards also included a 5-yard completion to Pierre Garcon that put Manning in some very exclusive company as the only quarterback in NFL history to throw for 40,000 yards in a single decade.

With Indianapolis (8-0) staked to a fast start on the scoreboard, it allowed the youthful defense the opportunity to relax and focus on making plays.

That youth movement was served quickly. On Houston’s ensuing possession, Colts rookie cornerback Jerraud Powers picked off a Matt Schaub pass to set Indianapolis up on the Texans’ 41.

The Colts drive would stall inside the 5-yard line, but a 22-yard field goal from veteran Matt Stover put the hosts up 10-0 just over 11 minutes into the contest. Stover would give Indy a 13-0 lead with a 37-yard kick early in the second quarter.

While Manning carved up the Texans defense early on, Houston’s offense found its footing incredibly difficult to locate as well. In fact, the Texans didn’t record a first down until midway through the second quarter.

By that time, Colts defensive end Dwight Freeney had already collected 1 1/2 sacks, and Indy had seemingly taken control.

“We were a little out of sync,” Texans coach Gary Kubiak said. “We script that opening, those first 15 plays, and practice them over and over again. We just made mistakes.

“We put our defense out there I think three times in a row. To put that out there, that many times, especially in this stadium, we were lucky that we were only down 10-0.”

Freeney collected his first sack on Houston’s first offensive play, setting a new Colts record with a sack in his ninth consecutive game, breaking a mark set in 2005 by teammate Robert Mathis.

The Texans finally started moving the ball late in the second quarter in an effort to get back within striking distance. Houston converted on a 4th-and-1 from the Colts’ 31 in the drive, as Schaub found standout receiver Andre Johnson for a 10-yard completion.

Houston continued to show signs of life, threatening to pull within a touchdown as the clock neared the 2:00 warning. Texans running back Ryan Moats got down inside the Colts 2, apparently fumbling the ball away in the process.

“(That was a) big turnover there on the 2-yard-line,” Kubiak said. “Our turnovers ultimately hurt us at the end of the day. Turnovers are what get you beat.”

Following the break and after a lengthy review, referee Jeff Triplette ruled that Powers ultimately recovered the ball as it rolled into the end zone, giving Manning two full minutes to work with.

“We initially thought that he was out of bounds with the ball as he possessed it, but it actually came loose prior to going out of bounds,” Caldwell said.

That two minutes provided several momentum swings. Manning quickly drove the Colts deep into Houston territory before cornerback Bernard Pollard picked off a pass and returned the ball near midfield. The Texans picked up one first down before the Colts defense stiffened, forcing a 56-yard field goal attempt.

Indy’s Cody Glenn broke through to block the attempt — all for naught, however, as the Colts called timeout just before the snap. Given another chance, Kris Brown’s second attempt from 56 yards was good as the clock expired, cutting the Indianapolis halftime advantage to 13-3.

Houston rode that momentum to make things interesting to open the second half. The Texans limited Indy to a single three-play drive, outgaining the Colts 122-7 in the stanza.

“Defense got us in the game,” Kubiak said.

With 8:36 remaining in the third, Schaub connected with Moats from a yard out to cut the Colts’ lead to three, then Steve Slaton’s 1-yard dive on the fourth quarter’s initial play gave the Texans the advantage at 17-13.

“I am proud of our team’s effort, they played hard,” Kubiak said. “Obviously, we had a chance at the end to still be out there playing.”

The Colts were down, but definitely not out. Not with Manning and his now 39 career fourth-quarter and overtime comebacks.

Finding a nice mix of Manning’s passing effort with some hard running by Joseph Addai, the Colts would mount one final scoring drive. Addai’s 2-yard rumble with 7:16 remaining would provide Indy with a 20-17 lead.

“I think we were pretty efficient,” Caldwell said. “There were times when we needed to run it, particularly on that drive. We ran the ball pretty well. Joseph had some pretty nice runs.”

Despite the lead, Houston still had two shots to rally. Indianapolis’ defense had other ideas, though, as Clint Session picked off Schaub with 2:20 left. When the Colts’ offense came up empty on the ensuing possession, it left the Texans with one final drive.

Schaub would guide Houston into position to tie the contest before Brown’s kick missed wide left, leaving the Colts’ perfect record intact and Kubiak to wonder what exactly it is that makes Indianapolis the class of the AFC South.

“They play all they can play,” Kubiak said. “They win whenever they have to win. When the game is going on, they make the plays they need to.”

Notes: The announced attendance was 66,033 ... Caldwell became the first Colts head coach and first head coach in the Super Bowl era to start 8-0 ... Tight end Dallas Clark tied a Colts record with 14 receptions, matching Marvin Harrison, who completed the feat twice ... Indianapolis extended its franchise record with a 17th consecutive regular-season victory, becoming only the fourth team to earn a streak of at least 17 straight wins in the regular season.