Rory McIlroy and Graeme McDowell underlined their potential as a possible Ryder Cup pairing with a hard-fought four-under-par 68 in Friday's foursomes at the Omega Mission Hills World Cup to maintain Ireland's three-stroke advantage.

After posting a brilliant 14-under-par fourballs score of 58 on Thursday, McIlroy declared he hoped European Ryder Cup captain Colin Montgomerie was watching.

And while that bogey-free round is certainly the highlight of the week in China, the battling display further underlines their bond with an eye on Celtic Manor next year after they also combined to win three out of four matches in September's Vivendi Trophy victory.

"Everyone knows I'd love to play with Graeme in the Ryder Cup, there would be nothing better," said world number 10 McIlroy.

"I think we would make a great team, although it's not up to me to decide and we've still got a long way to go, we still have to make the team.

"We do team up very well and I think that showed today. It wasn't the easiest of 68s by any means, but we ground it out and we put together a good score."

Ireland led by five shots at the turn, but with defending champions Henrik Stenson and Robert Karlsson of Sweden mounting a late charge which would see them move into second with a bogey-free seven-under-par 65, McDowell plunged his approach at the heavily guarded 15th into the water.

After he missed a long downhill par putt, McIlroy's recent problems with short putts returned with a two-foot miss which resulted in an ugly double-bogey.

The pair regrouped, though, and McDowell holed back-to-back birdie putts to maintain the lead ahead of Saturday's return to fourballs.

Montgomerie has already recognised McIlroy is a virtual certainly to qualify for a maiden Ryder Cup appearance next year, but McDowell's selection is seen as less of a formality with the strong state of European golf.

But their performances as a pair fighting for every shot this week could boost McDowell's chances of a captain's pick, if he missed out on an automatic place.

"We showed tremendous character after the double bogey on 15 to come back with those two birdies," added McIlroy.

"We didn't let a couple of mistakes get us down. We talked about body language on 16 after walking off the tee box saying let's walk positively up this fairway and try and get a couple back, and that's what we did."

Stenson and Karlsson combined to shoot the only bogey-free round of the second day's foursomes as last year's winners moved into second place following late back-to-back birdies.

Italian brothers Francesco and European Challenge Tour number one Edoardo Molinari, fresh from last week's win at the Phoenix Tournament in Japan, sit third a further shot off the pace following a six under 66.

Japan's Hiroyuki Fujita and Ryuji Imada are three shots further back in fourth at 11 under after a 71.

"I think we are right where we expected to be if we played well, to be up there with a few of the teams that we would also expect to be up there," said world number eight Stenson.

"Ireland was definitely one of them, and also Italy. Unfortunately, Edoardo beat my team-mate last week in a play-off, and Francesco has played good all year, so we kind of expected Italy to be up there as well.

"We are in a good position, and we just need to keep on playing as well as we have over the first two days for the next two days and we'll have a chance."