US Open 2014 leaderboard: Martin Kaymer stretches his lead to evoke memories of Rory McIlroy's runaway lead in 2011

Kaymer started on the back-nine and covered in in 31 to take a five-shot lead

Martin Kaymer leads the US Open by five shots on day two (Getty Images)

Ryder Cup hero Martin Kaymer evoked memories of Rory McIlroy's runaway victory in 2011 as he continued to dominate the 114th US Open.

Kaymer's opening 65 was the lowest score ever in the US Open at Pinehurst, eclipsing the 66 recorded by Sweden's Peter Hedblom in 2005 and giving him a three-shot lead over the chasing pack.

And the 29-year-old German swiftly extended his advantage to six shots as he looked to repeat his wire-to-wire victory in the Players Championship last month and become the first player to win golf's so-called unofficial 'fifth major' and the US Open in the same year.

Kaymer had covered the back nine in 31 on Thursday and quickly demonstrated his liking for it on Friday, making light of the 627-yard par-five 10th - his opening hole - by holing from six feet for birdie.

The former world number one missed from 12 feet for birdie on the 12th but quickly made amends, holing from twice the distance on the next. He looked in danger of dropping a shot when he raced his birdie putt on the 14th 10 feet past the hole, but calmly holed for par and then got up and down from a greenside bunker on the 15th.

Another birdie from 25 feet on the 16th took Kaymer to eight under par and brought to mind McIlroy's record-breaking victory at Congressional; the Northern Irishman's winning total of 16 under par was the lowest in championship history, while he was also the first player ever to get to double digits under par in the first two rounds.

Asked on Wednesday what score he would be happy with after four rounds, Kaymer had said eight over par. At eight under after 27 holes, the former US PGA champion was six clear of Zimbabwe's Brendon de Jonge, American journeyman Fran Quinn and Dustin Johnson, with Graeme McDowell and Kevin Na among the later starters.

The last of Quinn's three previous US Open appearances was 18 years ago and he was a combined 25 over par in his national championship before shooting a two-under 68 on Thursday.

"It is only one round, but it's nice to put up the great score the first day," Quinn said. "But you know you have to keep it going. It was everything that I could want and more. It's a dream and I hope I don't wake up until Sunday."

The 49-year-old, whose 15-year-old son Owen is caddying for him this week, had birdied the first and third to move into outright second but dropped shots on the fourth and fifth.

US Open 2014 leaderboard:

8 under - Martin Kaymer (Ger) (after 26 holes)

3 under - Francis Quinn (22)

2 under - Kevin Na (18)

Brendon De Jonge (Zim) (28)

Graeme McDowell (Nrl) (18)

Jimmy Walker (29)

Danny Willett (Eng) (24)

1 under - Hideki Matsuyama (Jpn) (18)

Gary Woodland (26)

Matt Kuchar (18)

Brooks Koepka (26)

Dustin Johnson (29)

Brendon Todd (18)

Brandt Snedeker (18)

Henrik Stenson (Swe) (18)

Jordan Spieth (18)

Level - Steve Stricker (28)

Lucas Bjerregaard (Den) (18)

Henrik Norlander (Swe) (18)

Joost Luiten (Ned) (18)

PA