The Indianapolis Colts are ahead by three points heading into the interval at the San Francisco 49ers, thanks to a long field goal from Adam Vinatieri.
Trent Richardson got the Colts off to a strong start at Candlestick Park on his debut, finishing off an opening drive of 80 yards with a touchdown carry of a single yard.
San Francisco responded strongly as Frank Gore helped drive the hosts downfield, with Kendall Hunter levelling things up with a 13-yard run into the endzone.
Midway through the second quarter the Colts took full advantage of Reggie Wayne's first catch of the night to get into field-goal rage, with Vinatieri making no mistake from 43 yards.
The 49ers lost safety Raymond Ventrone through concussion late in the first half, with the Colts holding on for a 10-7 advantage at the break.
Liam Power
