Tip from Rory McIlroy, one of the main chasers, to Martin Kaymer, the main man, who they're pursuing: "Keep the foot to the floor, just keep it going!"

Who knows if Martin Kaymer – who carries a six-shot lead into the third round of the 114th US Open – will maintain his aggressive approach, or possibly switch to a more protective game in maintaining his cushion on the field, but McIlroy will go into the third round with flag-chasing shots on his mind as he seeks to chase down the German.

McIlroy, nine shots adrift of the leader, added a second round 68 to his opening 71 to reach the midpoint of this championship aware that this is now Kaymer’s to lose as much as it is anyone else’s to win.

Undeterred, the Northern Irishman insisted: “There’s a lot of golf left to play. So we’ll see what happens over the weekend.”

Of the challenge facing Kaymer in protecting his advantage, McIlroy observed: “If you get too defensive, it’s detrimental. So he has to just keep hitting to his spots, being aggressive . . . and if he does that and shoots a couple of 70s over the weekend, I don’t think anyone’s going to catch that.”

Kaymer – the 2010 US PGA champion – is six clear of Brendon Todd going into the third round round, with the following 26 players separated by five shots in a crowded chasing pack.

“If he’s comfortable out here and making birdies, then that’s what you should still be thinking of . . . 10-under par is an incredible total after 36 holes, and if he can hold on to that 10-under total, he’s going to win this tournament,” said McIlroy.

“I think what Martin’s doing is more impressive than what I did at Congressional, just because of how difficult the golf course is and there’s trouble lying at every corner at any missed green. Congressional was a little more benign than this is, a little softer, a little more receptive. So you know what Martin’s doing is very impressive . . . Martin’s a good front runner and I can’t see him sort of letting up.”