Clarets' Clockwatch:
20 A let off for Burnley as O'Brien rattles the crossbar
24 Elliott curls a shot from distance at Owls keeper Jones
36 The bar saves Burnley again as Brunt smacks the woodwork
46 Jensen gets down well to deny Bougherra on his line
53 Steve Jones' volley is way too high
60 Jensen saves again as O'Brien tries his luck from distance
61 Jones is again off target for the Clarets.
67 1-0 to the Owls as MacLean converts a clear-cut penalty.
82 GOAL! The Clarets equalise as James O'Connor slots home
90 Andy Gray is sent off for kicking the ball away.
JAMES O'Connor's late equaliser preserved Burnley's unbeaten start to the season and sent the Clarets back to the Championship summit.
The Clarets trailed to Steve MacLean's 67th minute penalty with time running out.
But substitute O'Connor popped up with a clinical close-range finish to earn a precious point at Hillsborough.
Burnley, unchanged from the midweek victory at Leicester, began brightly with Alan Mahon again roaming off the left touchline in support of strike pairing of Steve Jones and Andy Gray.
And the first real chance fell to Andy Gray on the quarter hour mark following a sweeping move down Wednesday's right.
Mahon found Jon Harley overlapping and the cross was nodded just over by the former Sheffield United striker, who appealed in vain for a push.
The action swung straight to the other end, where Chris McCann's slip allowed Burton O'Brien to advance before slamming the crossbar with a vicious 20-yard drive.
Wade Elliott responded for the Clarets with an ambitious curler from the corner of the area that keeper Brad Jones held comfortably.
But the bar again came to Burnley's rescue nine minutes before the break as the Owls, still searching for their first goal of the season, pieced together the move of the half.
Steve MacLean and O'Brien combined to supply Brunt, whose rising drive across Brian Jensen at full stretch struck the angle of bar and post to the Dane's relief.
And as the hosts ended the half on the front foot, the industrious O'Brien headed tamely across goal form the tightest of angles.
Half time came at a good time for Burnley, but Wednesday stepped up their offensive straight from the restart and Jensen was forced to make a smart instinctive stop on his line as Algerian defender Madjid Bougherra connected with Brunt's outswinging corner on the volley.
And in the 50th minute, The Owls had a goal disallowed for blatant pushing well before MacLean finally headed home.
Hillsborough smelt Lancashire blood and Jensen again needed to be on his toes to keep out O'Brien's skidding long-range effort.
But the breakthrough finally arrived in the 66th minute when Frankie Simek's run into the box was unceremoniously halted by Harley's clumsy challenge.
A penalty was the only option and MacLean capped the home side's growing spell of pressure with a confident spot kick that sent Jensen the wrong way.
Kyle Lafferty immediately made his entrance from the bench to replace Mahon, with James O'Connor soon following for Wade Elliott.
And it was O'Connor who came up trumps for the Clarets with eight minutes to go, slotting home form six yards after Chris McCann knocked down Frank Sinclair's cross.
The precious point was preserved when skipper Wayne Thomas got in a vital challenge to deny Brunt.
And the day ended on a low note when Gray, who had been booked in the 84th minute, who was sent off in the dying seconds for kicking the ball away in frustration at being flagged offside.
Gray will now miss next weekend's home clash with Wolverhampton Wanderers.
BURNLEY: Jensen, Harley, Thomas, Duff, Sinclair, Mahon (Lafferty 68), McCann, Hyde, Elliott (, J O'Connor 77), S Jones (Foster 90), Gray.
Subs not used: McGreal, G O'Connor.
Goals:
Bookings: McCann 71, Gray 84
Sent Off: Gray 90
OWLS: B Jones, Lunt (Small 85), Coughlan, Whelan, O'Brien, MacLean, Brunt, Hills, Simek, Bougherra, Spurr.
Subs not used: Adamson, McAllister, McArdle, Boden.
Goals: MacLean 67 (pen)
Bookings: Bougherra 84
Ref: Colin Webster
Att: 22,425
