Rickie Fowler is just one shot off the lead after a seven-under par opening round at the WGC-HSBC Champions in Shanghai.

The American was faultless in his opening salvo at Sheshan International, with no dropped shots on his scorecard. Rikard Karlberg of Sweden is the clubhouse leader overnight after a round of 64.

He began his round with four straight birdies and added four more on the inward nine before dropping his only shot of the day on the par-five 18th.

Behind the leading pair is a trio of three players on six-under par that includes defending champion Russell Knox of Scotland.

He is in company with Hideki Matsuyama and Daniel Berger. Paul Casey (-5), Sergio Garcia (-4), Henrik Stenson and Adam Scott (both -3) are some of the other big names off to quick starts.

Rory McIlroy, however, endured another frustrating day on what were wet and slow greens, the Northern Irishman making just two birdies is his round of one-under par.

McIlroy has playing partner Bubba Watson for company along with his Ryder Cup team-mates Thomas Pieters and Rafa Cabrera-Bello.

It may not have been the day McIlroy was hoping for, but he is in a much healthier state than his Hazeltine foe Patrick Reed.

The American dropped eight shots during a torrid seven-hole spell around the turn as he posted a six-over par round of 78 – leaving just four players in the 78-man field behind him.

Masters champ Danny Willett dropped five shots in four holes in the middle of his front nine before recovering to post 74.

He has the US Open champion Dustin Johnson beside him on +2, with the American unusually lacking punch as his round included just one birdie.