After spending most of his week in the trainer’s room, Reggie Wayne felt a little off course again Sunday with the football overhead and the game on the line.

“I felt like when I caught it, I was in there by the bathrooms,” the Indianapolis Colts wide receiver said.

Wayne chased down running back Joseph Addai’s pass deep in the corner of the end zone for the 22-yard fourth-quarter touchdown that lifted the Colts to a bitterly contested 18-14 victory over the San Francisco 49ers.

“Tuesday, I didn’t think I was going to play,” said Wayne, who was hobbled by a groin injury. “Wednesday, I didn’t think I was going to play.”

Wayne didn’t practice until Friday, but he was a man on a mission Sunday with bright sunshine pouring into Lucas Oil Stadium and a sellout crowd of 66,229 perched on seats’ edge. With the offense spinning its wheels all over the field, he made 12 catches for 147 yards and the game-winner.

“It was great to see him out there,” said Colts tight end Dallas Clark, who caught eight passes for 99 yards. “We needed him, big-time.”

The plunder was considerable:

The Colts are 7-0 for the fourth time in the past five seasons. They extended their regular-season winning streak to 16, fourth longest in NFL history, and they made Jim Caldwell the only coach in the Super Bowl era (post-1965) to start his rookie season 7-0.

More important, the Colts maintained a 21/2-game lead in the AFC South with second-place Houston (5-3) coming to town this week.

San Francisco (3-4) lost for the fourth time in its past five games.

Colts quarterback Peyton Manning might be the only player in the league who can pass for 300 yards and have an “off” game. Manning completed 31-of-48 passes for 347 yards but failed to throw a touchdown pass for the first time since a 10-6 victory last November at Cleveland.

The game was the last of the Colts’ season series with the NFC West, a four-game set whose first three they had taken by a 107-33 margin. Not Sunday. It was welcome back to the NFL. Nothing came easily.

“This was a fight,” said defensive end Dwight Freeney, whose eighth sack of the season killed the 49ers’ final possession.

The Colts hadn’t permitted a touchdown in eight quarters, but San Francisco took a 14-9 halftime lead on Frank Gore’s 64-yard touchdown run on their second possession and an 8-yard scoring pass from Alex Smith to tight end Vernon Davis near the end of the half.

With the Colts failing to score a touchdown in the red zone, Matt Stover kicked four field goals, but the home team still trailed for the first time since Week 2 at Miami.

Then Addai, a high school quarterback in Houston, took a handoff and started left on the stretch play on the first play of the fourth quarter. The 49ers reacted as one. They bit hard on the run.

“They got us on that one,” San Francisco coach Mike Singletary said.

Addai pulled up and lofted a high, lazy spiral toward the corner. Wayne, Addai’s training camp roommate and good buddy, had to run hard to catch up with it.

“I couldn’t drop that one,” Wayne said. “If I dropped that one, he would have messed with me forever.”

Smith, starting for the first time in almost two years, completed 19-of-32 passes for 198 yards with one interception. The Colts snuffed the 49ers’ final two threats with sacks by defensive end Robert Mathis, then by Freeney.

Gore’s 64-yard first-quarter touchdown run was a stunner, and a starter.

“It triggered us,” said linebacker Clint Session, whose eight tackles topped the Colts. “It triggered us to do the job.”

Gore gained only 27 yards on his other 12 carries. The defense kept it close. The offense finally got it done. The celebration can wait.

“We know (7-0) guarantees nothing,” Wayne said. “We’ve got in the past farther than this and came out with nothing. We just want to stay dialed in and continue to win games.”

The Colts and New Orleans (6-0), which plays Atlanta tonight, are the NFL’s lone remaining unbeaten teams.

A perfect ‘season’

Sunday’s win over the 49ers stretched the Colts’ regular-season win streak to 16 games. That’s tantamount to a full season. A look at quarterback Peyton Manning’s statistics during that 16-0 stretch:

[chart]
|Completions|396|
|Attempts|553|
|Pecentage|71.6|
|Yards|4,475|
|Touchdowns|32|
|Interceptions|7|
|Rating|109.4|
|Sacks|10|
[end chart]

[chart]
||||||||
|San Francisco|7|7|0|0|—|14|
|Indianapolis|3|6|3|6|—|18|
[end chart]

SF—Gore 64 run (Nedney kick), 11:16.

Ind—FG Stover 38, 3:16.

Ind—FG Stover 33, 14:50.

SF—V.Davis 8 pass from A.Smith (Nedney kick), :33.

Ind—FG Stover 31, :01.

Ind—FG Stover 40, 9:34.

Ind—Wayne 22 pass from Addai (pass failed), 14:53.

A — 66,229.

[chart]
|Team Statistics|SF|Ind|
|First downs|16|20|
|Total Net Yards|295|410|
|Rushes-yards|18-113|21-61|
|Passing|182|349|
|Punt Returns|6-37|6-32|
|Kickoff Returns|6-102|3-64|
|Interceptions Ret.|0-0|1-29|
|Comp-Att-Int|19-32-1|32-49-0|
|Sacked-Yards Lost|4-16|3-20|
|Punts|8-50.0|7-46.3|
|Fumbles-Lost|2-1|2-0|
|Penalties-Yards|7-50|5-38|
|Time of Possession|26:26|33:34|
[end chart]

RUSHING - San Francisco, Gore 13-91, A.Smith 1-10, Coffee 1-8, Norris 3-4. Indianapolis, Addai 20-62, Simpson 1(minus 1).

PASSING — San Francisco, A.Smith 19-32-1-198. Indianapolis, Manning 31-48-0-347, Addai 1-1-0-22.

RECEIVING — San Francisco, Crabtree 6-81, Gore 5-43, Bruce 4-51, V.Davis 3-20, Morgan 1-3. Indianapolis, Wayne 12-147, Clark 8-99, Collie 6-66, Garcon 4-53, Addai 2-4.

MISSED FIELD GOALS — None.