Final Score: Indianapolis 18, San Francisco 14

Indianapolis, IN (Sports Network) - Peyton Manning threw for 347 yards, but it was Joseph Addai who threw the game-winning TD pass to Reggie Wayne in the fourth quarter, as the Indianapolis Colts survived a tough test from the San Francisco 49ers and kept their undefeated season intact with an 18-14 victory at Lucas Oil Stadium.

Manning was not at his sharpest despite logging his sixth 300-yard passing game of the season, connecting on 31-of-48 throws and becoming only the fourth player in NFL history to reach 4,000 completions. He was also sacked three times -- something that had happened only two previous times this season and not at all in the last five games.

In addition to throwing his first career touchdown pass, Addai ran for 62 yards on 20 carries, while Wayne shrugged off a groin injury to tie his career-high in catches with 12 for 147 yards and the all-important go-ahead score just seconds into the final quarter. Wayne has caught a touchdown pass in five consecutive games and in six of seven tilts this season.

Matt Stover did most of the damage, hitting all four of his field goal attempts for the Colts (7-0), who extended their franchise-record regular- season win streak to 16 games. It's the longest active streak in the league and tied for fourth longest in NFL history.

The win also represents the fourth time in the last five seasons the Colts have started 7-0.

Alex Smith, getting the start after replacing an ineffective Shaun Hill in last week's close loss to Houston, completed 19-of-32 passes for 198 yards with one score and an interception.

Vernon Davis, who came into Sunday leading the league in TD receptions, had another during a three-catch, 20-yard day. Frank Gore had a 64-yard TD run and finished with 91 yards on 13 carries.

Michael Crabtree caught six passes for 81 yards for the 49ers (3-4), who lost their third straight and fourth in the last five games.

"We are young and we have to learn how to win those games. We have to learn how to finish those games," said 49ers head coach Mike Singletary, referring to his team losing four of its five games by four points or less.

After trailing for the first time all season entering the second half, Indianapolis put together its most sustained drive of the game to that point -- an 11-play, 52-yarder that ended with a 40-yard field goal from Stover, his fourth of the game.

Indy gained a short field after Crabtree fumbled it away on the 49ers' next series, but the defense forced a three-and-out to hold the two-point edge.

But San Francisco failed to move the ball and the Colts set out from their own 30 and finally found the end zone on the first play of the fourth quarter. An 11-yard pass to Wayne and a neutral zone infraction kept the chains moving on a pair of third-down plays before first-year head coach Jim Caldwell reached into his bag of tricks in the red zone.

Addai took a handoff, but rolled left and hit Wayne in the back left corner of the end zone for a 22-yard score. Manning attempted a two-point conversion try, but threw it over the head of Pierre Garcon as the Colts took an 18-14 lead.

"We have a pretty good arsenal of things that we use. That one we've been working on for a long time," Caldwell said of Addai's surprise halfback toss. "The situation was right and he did a nice job of throwing it."

The Colts' defense took care of the rest as Robert Mathis sacked Smith on 3rd- and-12 at the Indy 35 on the ensuing series and Dwight Freeney did the same on third down near the six-minute mark. It was Freeney's eighth consecutive game with a sack, tying a team record held by Mathis.

It was also the last time San Francisco had the ball, as the Niners punted away with 5:57 remaining and Manning orchestrated a drive from his own 33 that ran out the clock.

"It was just kind of one of those days, never found much rhythm. We just kind of kept grinding it out. Fortunately our defense kept them from scoring a lot, so we were able to keep the game close," Manning said.

San Francisco used the legs of Gore and took advantage of some shoddy tackling by the Colts to score the game's first points. Gore trudged through the middle of the line, shed two linebackers and found daylight up the seam for a 64-yard touchdown just 3 1/2 minutes in.

The 49ers' defense forced Indy into a three-and-out on its first two tries, but Manning and company got on track for a 10-play, 57-yard drive that ended with a Stover 38-yard field goal late in the first.

Bob Sanders notched his first interception of the season on the ensuing possession, hauling in a tipped ball off the hands of Crabtree and the Colts were back in business at the San Francisco 34.

The 49ers defense did well to hold the Colts to three, though, as they settled for a 33-yard boot from Stover just over a minute into the second.

Both defensive units dominated for much of the first half as San Francisco had just one first down following the Gore TD until after the two-minute warning, and the normally potent Colts attack was held in check.

San Francisco got the ball back just past the two-minute mark and Smith moved the ball with ease in a hurry-up offense. A 27-yard completion to Crabtree was followed by a 12-yard pass to Isaac Bruce and a 10-yard toss to Davis, which brought the ball across midfield.

A short pass to Gore turned into a big play on a roughing-the-passer call that placed the ball at the 12, and two plays later Smith hit Davis for an eight- yard touchdown and a 14-6 lead with 33 seconds left.

The Colts managed a 31-yard kick by Stover in the remaining time for a 14-9 game at the break.

While the 49ers' defense did a good job in the first half, Manning also misfired on a couple of potential big plays. He overthrew Wayne on a deep ball up the left sideline and underthrew Garcon, who was in stride running up the seam.

Game Notes

Smith saw his first regular-season action since November of 2007 during last week's 24-21 loss to the Texans. Sunday was the former No. 1 overall pick's first start since Week 9 of that season...Indianapolis holds a 24-18 edge in its all-time series with San Francisco, and snapped a two-game skid in the series with a 28-3 win at Candlestick Park in 2005...Colts running back Donald Brown was held out of the contest with a sprained shoulder, as was defensive back Marlin Jackson due to a knee injury...It was Manning's first game without a touchdown pass since Week 12 of last season, a 10-6 win against Cleveland...Crabtree made his NFL debut last week for the 49ers and already has 11 catches for 137 yards...Caldwell became the first rookie coach since the NFL merger to open his career with seven consecutive wins. It's the second best start in league history to a career with Potsy Clark having won his first eight for the Portsmouth Spartans in 1931...Manning was the fastest to 4,000 completions (183rd game).