David Lynn and Marcel Siem carded matching rounds of 1-under 71 to share third place at 7-under-par 137.
Green did not get off to the start that would make him think he would share the lead at the midway point at the Arden Course at Marriot Forest of Arden Hotel & Country Club. He hit a poor second shot at the par-5 third hole and left with bogey but rebounded at the short par-4 fourth. He chipped his second shot in from 51 yards out to go 1-under for the round.
'I just tried to play in a nice pitch close and it decided to go in,' said Green, referring to his play at the 381-yard fourth hole. 'I saw it go in and that really kick-started my day. It gives you a nice feeling and kicks you off.'
Green took advantage of the next par-5, the 524-yard seventh. He reached the green in two with a 6-iron and two-putted for his first birdie of the round. He made it two in a row with a nine-foot birdie putt at the eighth to make the turn at 3-under 33.
Green played steady golf on the second nine with six pars in a row to open. He birdied 16 and 17 for the second time in as many days and closed his round with a 5-iron approach to 12 feet to set up birdie and reach the top of the leaderboard.
'I've made a pact this week that I am not going to change my routine, no matter how hard the shot or how easy,' said Green, who became the first left- hander to win on tour since 1975 when he outlasted Ian Woosnam and Greg Norman in a playoff at the 1997 Dubai Desert Classic. 'It's going to be the same every time. It's worked the first two days and I hope it does for the next two.'
Owen started on the back nine Friday and broke into red figures quickly with a 12-foot birdie putt at No. 10. He added a pair of late birdies, including a near chip-in at 18, for a first-nine 33.
Owen collected eight pars on the front side but played the seventh in similar fashion to Green. He landed on the green in two with a 6-iron and two putts later it was a birdie and a share of the second-round lead with Green.
'On this course you can get low scoring or it can come up and grab you,' said Owen, who is winless on the European Tour. 'I have just got to be patient and just try to play the game and keep the scoring going.'
That was Owen's second round without a bogey on Friday. His last mistake hole was a double-bogey at the fourth hole in the third round of last week's Wales Open at Celtic Manor Resort.
Darren Fichardt (66), Matthew Blackey (68) and Mikael Lundberg (69) share fifth place at 6-under-par 138. Ignacio Garrido, the winner of the Volvo PGA Championship two weeks ago, is alone in eighth place at minus-5.
Peter Fowler, the first-round leader, shot a 3-over 75 on Friday and is part of a group in ninth place. Stephen Gallacher and Jean-Francois Lucquin shot matching rounds of 1-under 71 and joined Fowler at 4-under-par 140.
Justin Rose, the 2002 British Masters champion, struggled to a 3-over 75 on Friday and made the 36-hole cut on the number at even-par 144.
Colin Montgomerie was not as fortunate as Rose. He carded rounds of 73-75 and missed the cut at 4-over 148. Montgomerie, who also missed the 36-hole mark last week in Wales, is now limping into next week's U.S. Open at Olympia Fields Country Club outside of Chicago.
'In the past, I've missed a couple of cuts and then I won the BMW after I missed in Switzerland and somewhere else, so yes of course there are quick turn-arounds,' said Montgomerie, who lost the 1994 U.S. Open in a playoff to current Order of Merit leader Ernie Els. 'Whether I have enough time to turn it around before next week, I'm not sure. But I'll turn it around soon, it is just a matter of when.'