The Kansas City Chiefs are trailing the San Francisco 49ers, 9-7, at halftime at Arrowhead Stadium as the two teams kick off the preseason.

Chiefs quarterback Alex Smith completed four of six passes for 48 yards and added 10 yards on the ground in his one series of work, leading Kansas City on an eight-play touchdown drive.

Smith hit wide receiver Tyreek Hill for 32 yards down the sideline on the first play of the game before running back Spencer Ware later plowed ahead two yards for the score.

Chiefs quarterback Tyler Bray was under center for the majority of the half, completing five of eight passes for 63 yards and an interception. Rookie quarterback Patrick Mahomes  made his professional debut with 6:44 left in the half, completing both of his pass attempts for 13 yards.

Mahomes initially connected on a 41-yard strike to Demarcus Robinson on the first play of his professional career, but it was wiped out by an offensive holding call.

San Francisco tallied a pair of unanswered field goals to chip away at the deficit before taking the lead midway through the second quarter on a 27-yard field goal by Nick Rose.

Chiefs defensive tackle Ricky Ali'ifua blocked a fourth San Francisco field goal attempt as time expired in the half.

Tune in to KCTV5 or 101.1 The Fox to catch the second half of action.