Omar Uresti carded a third-round 66 and shares third place with Tag Ridings, who shot a five-under 67 Saturday. The pair completed 54 holes at 13-under-par 203.
Winston, who shared the second-round lead with Gene Sauers, didn't get off to a good start Saturday when he three-putted the first green for a double-bogey. He rebounded with three birdies in a row, starting at the second, but promptly dropped another shot at the fifth.
Winston's wild front nine continued with a five-foot birdie at the sixth but he followed with a bogey at No. 7. He closed his front nine with a seven- footer for birdie at the ninth.
The 30-year-old Buy.com Tour rookie steadied himself on the back nine. He birdied the par-5 12th and drained a 15-foot birdie at the 16th to join Hensby in first.
'I didn't putt as well as I have been,' said Winston, who needed only 26 putts on Saturday. 'I just tried to keep focused. The three straight birdies helped out.'
Hensby, who played in the group ahead of Winston, sandwiched a bogey around two birdies early in his round but his play on the second nine propelled him into a share of the lead.
Hensby birdied the par-5 12th and capitalized on the next par-5, the 601-yard 15th. He knocked an eight-iron to eight feet to set up a birdie and added a 12-foot birdie at 17 to reach 16-under par.
He would have been alone in the lead but a bogey at the 18th gave him a four- under 68 and meant he would share the top spot heading into the final round.
'I hit the ball well but I didn't make anything,' said Hensby, a two-time winner on the Buy.om Tour. 'I'm surprised to still be close to the lead. Tomorrow on the last nine holes is what it is all about.'
Uresti's round was highlighted by a pair of chip-ins at the eighth and 14th holes. The chip-in birdie at No. 14 tied him for the lead but a bogey at the 15th dropped him into a tie with Ridings.
Chad Wright is alone in fifth place after a seven-under 65 moved him to 12- under par.
Brian Claar (67), Jeff Hart (68), Michael Flynn (68), Tom Carter (69), Brad Adamonis (71) and Sauers (74) share sixth at minus-10.
Full Field Scores from the Buy.Com Permian Basin Open