Khan claims clubhouse lead
Down in 31st place at halfway, the 2010 BMW PGA Championship winner even held a two stroke lead after going to the turn in 30 and adding two more birdies in the next four holes.
But while he parred in and set the clubhouse target of 12 under par, compatriot Chris Wood was also flying through the field.
Best known for his challenges at the 2008 and 2009 Open Championships, Wood covered the front nine in 31 and followed that with an eight foot eagle putt on the 548 yard tenth.
That put Wood 14 under, two ahead of Khan and Spanish star Sergio Garcia, who birdied the first, fourth and sixth.
“It's been a tough couple years since winning Wentworth, so it's amazing,” said Khan, who has had just one top-ten finish since holding off Luke Donald.
“The feelings start coming back pretty quickly in this game, which is good. Hopefully I can carry it on tomorrow.
“It was really good fun on the front nine, and I had a good up and down out of the waste area on three, which is a real tough one. I managed to par that and that really kept me going.
“I'm pleased with the back nine. I played quite nicely - left a couple of putts short but haven't been up there for a while, so hopefully I can do that a little bit better tomorrow.”
Kaymer birdied the second, but then three-putted the fourth and sixth, while Fraser fell all the way to 20th with bogeys at the first and sixth, but Santos was still in the thick of things at ten under.
World Number Four Justin Rose, five under par when he resumed, remained deep in the pack after parring every hole on the outward half.
Runner-up in Abu Dhabi last weekend, Rose did then birdie the long tenth, but then came two bogeys in the next three.
Wood three-putted the 12th, but came back with further birdies at the 14th and 16th and matched Khan's 64.
At 15 under he was two in front of Garcia, who still had five to play, and three clear of Khan, New Zealander Michael Campbell and Swede Alex Noren.