Bernd Wiesberger birdied the last hole to take a one-shot lead after the first round of the Nedbank Golf Challenge on Thursday.
Wiesberger broke clear of the pack with a superb approach to No. 18 to set up his birdie, finishing with a 5-under 67 to edge four other players.
Wiesberger made his move on the back nine with three straight birdies on Nos. 10-12 and another two on Nos. 14 and 16 before finishing with the birdie that gave him the outright lead. That was the last of eight birdies on the day for the Austrian.
Fleetwood has won twice this season on the way to the top of the Race to Dubai standings but he couldn't find his best form on Thursday. Fleetwood made three bogeys and two birdies to leave himself plenty of work to do to win the European title ahead of the season-ending Tour Championship in Dubai.
Noren made eagle at No. 10 and started his defense strongly a year after a sensational final round won him the Nedbank title.