The two top-ranking players in the World – Luke Donald and Rory McIlroy – were both staring at early exits from the US Open in Friday’s second round at San Francisco’s Olympic Club.

World No.1 Donald carded a deflating nine over 79 on Thursday, 13 shots behind surprise first round leader, 27-year-old US qualifier Michael Thompson, who had a 66.

The Englishman needed a minor miracle just to make the cut, but after 10 holes he had slipped out even further to stand at 10 over.

World No.2 and defending champion Rory McIlroy started the day at seven over and after 10 holes he was further adrift at eight over.

Playing in the same group as Donald and McIlroy, world No.3 Lee Westwood was steady, staying at three over.

Graeme McDowell, the 2010 US Open champion, who was one of five players tied for second, three strokes behind Thompson, was the main early mover with three birdies against two bogeys to get to two under for the tournament through eight holes.

Thompson, was not due off until 12:52pm on Friday (05:52 AEST on Saturday) from the ninth tee, with Tiger Woods, among those tied for second after an opening 69, setting off from the first tee 26 minutes later.

Woods, seeking to bag a record fifth US Open title, four years after he won the last of his 14 majors at the 2008 US Open, will have the company of Phil Mickelson and Bubba Watson who are also in a battle to make the cut after scores of 76 and 78 Thursday.

Weather conditions were again ideal with sunshine and little wind, but such is the severity of the par-70, 7,170-yard hillside layout that only six players out of a starting field of 156 were under par when the second round commenced.