The Chilean carded four birdies and two bogeys at Diamond Country Club on Friday to get to nine under par and maintain the two stroke advantage he held at the end of round one.
Afternoon starter Graeme Storm sat alone in second on seven under after mixing five birdies with two bogeys in his second-round 69.
Englishman Oliver Fisher and Swede Johan Carlsson were a further shot back in joint third, while David Horsey was among the group on five under after producing an eight-under-par 64 to equal the course record.
Overnight leader Aguilar, starting his second round at the tenth tee, slipped back to six under after dropping a shot at the 12th.
He soon bounced back, however, picking up shots at the two par fives on the back nine – the 15th and 16th – to move to eight under.
Aguilar rolled in his tricky birdie putt from 20 feet at the fourth before coming agonisingly close to making further gains at the sixth and seventh.
The 42 year old sent his approach at the eighth to within ten feet of the cup before sinking his birdie putt to get to ten under.
But after finding trouble off the tee, Aguilar dropped a shot at the ninth to head into the weekend on nine under.
“It was very difficult after five holes, the wind really picked up, the greens are getting hard and it is difficult to get it close and you have to calculate every time ten yards short, especially if you miss the fairway.
“So it was very difficult and unfortunately I finished with a bogey but overall it was a pretty good round. You are going to make some mistakes today but you just have to make sure you make some birdies as well.
“There is still a long way to go and I just want to put myself in contention and then we will see what happens on the weekend” – Felipe Aguilar
“I have been playing better but I haven’t been able to score. My putting is better, especially my irons and off the tee. I think I have been playing much better for the last eight weeks but I haven’t been able to score and I think the difference is confidence, and this week the confidence is much better.
“There is still a long way to go and I just want to put myself in contention and then we will see what happens on the weekend.”
Storm, who began the day three shots behind Aguilar, made a fast start, notching birdies at the second and fourth to get to six under.
The Englishman dropped his first shot of the day at the ninth but bounced back straight away with a gain at the tenth.
A second bogey followed at the 11th but Storm fired birdies at the 13th and 16th to get to seven under before pulling off a phenomenal par save from long range at the 18th to stay two shots behind Aguilar.
He said: “It was really difficult out there. The wind was really blustery and the fairways are really firming up and so are the greens.
“I struggled a little bit again today, I don’t feel as though I am swinging it correctly or hitting the ball great.
“I am just trying my best to get round and managing to put a score together, and getting a little bit of luck as well.”