Nothing came easily for the Indianapolis Colts in their narrow win over San Francisco on Sunday.

Consider it a precursor.

The road ahead for the AFC’s lone unbeaten team appears much more perilous than the road just traveled.

“We’re heading into the teeth of our schedule,” quarterback Peyton Manning said after directing the 38th fourth-quarter/overtime comeback of his career in the 18-14 victory.

The Colts have opened 7-0 for the fourth time in five seasons by taking care of business against teams with a combined 17-33 record. Only Arizona (4-3) has a winning record.

The next four games are against teams that are 19-11. The tough stretch begins and ends against the Houston Texans (5-3), who visit Lucas Oil Stadium on Sunday before hosting the rematch Nov. 29. Sandwiched in between are the latest Game of the Century against Tom Brady and New England (5-2) on Nov. 15 and a Nov. 22 trip to Baltimore (4-3).

Coach Jim Caldwell was in no mood to chew on the four-game grind that awaits his team. Sunday’s showdown with the Texans is all that matters to him. The others can wait.

“How about the next one?” he asked Monday afternoon.

The Texans have won three straight and have a winning record this late in the season for the first time in their eight-year history. If Manning and receiver Reggie Wayne aren’t the most potent pass-and-catch tandem in the league, it might be Houston quarterback Matt Schaub and receiver Andre Johnson.

“One of the things you always look for (are) the teams that are hot right around this time of year,” Caldwell said.

The Colts’ quick start is just their latest, and threatens to drain any suspense out of the AFC South race. A win Sunday over Houston and they’ll have a four-game lead with eight to play, virtually assuring a sixth division title.

Maintaining their 16-game regular-season winning streak could be problematic depending upon their health at cornerback. Kelvin Hayden’s status for Sunday is uncertain after he suffered a knee injury and concussion against the 49ers. Caldwell was unable to provide an update on Hayden, but said Marlin Jackson, who has missed the past two games with a left knee injury, might return.

If Hayden and Jackson both are out, the available corners would be rookies Jerraud Powers and Jacob Lacey, Tim Jennings and T.J. Rushing.

The Texans no longer are a soft touch, and seldom have been for the Colts. They trail the overall series 13-1 and have lost four straight, but four of the past five games have been decided by six points or fewer.

That includes a pair of losses last season that had the Texans wondering what went wrong. They led 27-10 with less than five minutes remaining in Reliant Stadium only to self-destruct and see the Colts scramble back for a 31-27 win. In the Indy rematch, the Colts trailed 13-9 at the half before rallying for a 33-27 win.

“We know them. We know what to expect,” said running back Joseph Addai, a Houston native.

To listen to the Texans, in the past they hoped to win. Now, they expect it. They trailed 10-6 at halftime at Buffalo on Sunday but never panicked, regrouping to outscore the Bills 25-0 in the second half.

“At no point did we panic and say, ‘Here we go again,’ " cornerback Dunta Robinson said after Houston’s 31-10 win. "Coming into games you hear guys say, ‘Hey, fellas, we’re supposed to win this game,’ and we’ve never had that mentality around here.

“I like it.”

That type of mind-set undoubtedly contributed to the Colts overcoming an inconsistent offensive outing against the 49ers. Their defense kept the game winnable until the offense found a way with Addai’s 22-yard touchdown pass to Wayne.

“Winning in this league requires you find ways to win when things might not be going that well,” Caldwell said. “Things weren’t going well for us consistently, but yet we were still able to work through it.”

Sounds like a good blueprint for the next month, and beyond.