Bjorn had bogeys at the first and 18th holes in the second round in shooting 3-under-par 68 and is 8-under 134 for the tournament. Kevin Streelman, who was 3-over on the eighth and ninth holes Friday but still managed to be 2-under on the day, is in second at 7-under.
Streelman and Matt Kuchar, with a 68 Friday, put the United States in front of the team section of the tournament at 10-under 274. They lead second-place Denmark -- Bjorn and Thorbjorn Olesen -- by three strokes. Kuchar won the team title of the tournament in 2011.
Sixty players are invited to the World Cup of Golf. They take part in both individual and team competitions. The top two players from each country have their scores combined for the team score.
Ricardo Santos shot a 2-under 69 and Jason Day was 1-under in the second round to move into a tie for third at 4-under. Kuchar, Martin Laird (72 Friday), Stuart Manley (72) and Hideto Tanihara (67) are tied for fifth at 3-under.
Streelman was tied with Bjorn for the first-round lead and pulled away early Friday with birdies on the first four holes. He stumbled to a bogey at the eighth hole and a double-bogey 6 at the ninth. Streelman had eight pars and a 15th-hole birdie on his second nine.
Bjorn rebounded from the opening-hole bogey with three birdies in the next five holes. He added birdies a 13 and 17 for a cushion in the lead before the closing bogey.