|Second round leaderboard|
|-12 McIlroy (NI); -9 Horsfield (Eng), Gros (Fra); -8 Fleetwood (Eng); -7 Rock (Eng), Noren (Swe), Aphibarnrat (Tha), Molinari (Ita); -6 Grace (SA), McDowell (NI), Bjerregaard (Den), Fitzpatrick (Eng), Levy (Fra), Bertasio (Ita), Fichardt (SA), Zanotti (Par), Jensen (Den)|
|Selected others:-5 Westwood (Eng), Sullivan (Eng), Fisher (Eng); -4 Lowry (Ire), Ramsay (Sco), Gallacher (Sco), Wood (Eng); -3 Poulter (Eng); -2 Casey (Eng)|
Northern Ireland's Rory McIlroy stormed into the lead at the BMW PGA Championship after a seven-under 65 on day two at Wentworth.
The world number eight, who won here in 2014, is 12 under par, with England's Sam Horsfield and Frenchman Sebastien Gros his nearest rivals on nine under.
McIlroy holed four birdies in a row on the back nine in a bogey-free round.
England's Tommy Fleetwood, the Race To Dubai champion, stayed in touch on eight under after a round of 66.
Fleetwood's compatriot Robert Rock shot a 68 to move to seven under alongside Sweden's defending champion Alex Noren (68), Thailand's Kiradech Aphibarnrat (69) and Italy's Francesco Molinari (67).
Northern Ireland's Graeme McDowell is a shot back from that trio, after his 67 took him to six under alongside nine others, including overnight leader Lucas Bjerregaard of Denmark (73) and England's Matthew Fitzpatrick (71).
Former world number one Lee Westwood's round of 69 took him to five under, level with fellow Englishmen Andy Sullivan (68), Ross Fisher (68) and James Heath (67).
England's Paul Waring had the week's first hole-in-one - at the par-three fifth - en route to a 68 to sit three under overall.
The cut at the European Tour's flagship event came at one under.
Those missing the weekend include two-time major winner Martin Kaymer, former Masters champion Danny Willett, Tyrrell Hatton, Jamie Donaldson, Padraig Harrington and Andrew Johnston.
Another to miss out is Belgium's Thomas Pieters, who snapped an iron around his neck after a poor shot on the par-five fourth.
Horsfield and Fleetwood lead England's challenge
Horsfield, the world 285, only turned professional last year and is playing in his debut season on the European Tour.
The Orlando-based golfer, who was born in Manchester, bogeyed the 17th and holed a par on the 18th to card a 68 to add to Thursday's 67.
"I think any time you're playing on the weekend and you're up there near Rory, I think you're going to be doing pretty well," said Horsfield.
World number 12 Fleetwood chipped in for birdies on the 13th and 16th and finished strongly with three birdies.
"It is nice to have made some ground on him, but giving Rory headway is never a good way to success, but you never know," said the Southport golfer.
"I am in a very good spot for the weekend."
McIlroy's 'best' round of 2018
Four-time major champion McIlroy had trailed by two shots overnight, and missed short putts on the first three holes.
But he led by the turn after three birdies and extended his advantage by gaining shots on the 12th, 13th, 14th and 15th.
He was unable to birdie the 16th or 17th and had to settle for another par on the 18th after his approach to the par-five green plugged in a bunker.
"On the first three holes I hit it to six to eight feet and none of them went in and I thought 'Here we go'," said McIlroy, who has the second lowest 36-hole total in the tournament's history.
"But I played great after that. It was one of the best rounds of golf I've played this year, ball-striking-wise.
"I had everything sort of firing today and it was nice to take advantage of the opportunities I gave myself.
"There's a lot of guys still to go out but hopefully I keep the lead and will be in the final group tomorrow. It will be nice to go out and feel that."
He added: "It's nice to live up to the billing [as pre-tournament favourite]."
Playing partner Noren said: "That's the best round I've ever seen." He then joked: "I'm about to quit golf, I think."
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