Swedish amateur Karlsson tied for lead after first round at Nordea Masters

Swedish amateur golfer Robert Karlsson was on top on the leaderboard with countryman Alexander Noren and Jaco Van Zyl of South Africa after they shot 5-under 67s in Thursday's first round of the Nordea Masters.

The 22-year-old Karlsson, one of only three amateurs in the tournament, made seven birdies and one double-bogey on the 7,603-yard (6,952-meter) Bro Hof Slott course -- the longest on the European Tour this year.

Karlsson said the lead took him by total surprise.

"We had set no goals aside from just having fun," Karlsson said of his caddie. "I hadn't really expected this when I stood by the tee this morning. It feels really good. I started to feel more and more comfortable with the shots and then it just kind of flowed. It felt like I was in the moment the whole time. I wasn't thinking either back or forward, I was just in the moment."

Noren made eight birdies, one bogey and a double bogey, while Van Zyl holed six birdies and a bogey.

Dustin Johnson, who shared second place in the British Open on Sunday, hit a 73 while fellow American Bubba Watson shot a 71.

Local favorite and defending champion Richard S. Johnson hit a 70.

The tournament changed its name to Nordea Masters from Scandinavian Nordea Masters this year.