FULL TIME: Leeds United 1 Sheffield Wednesday 0 - Jack Harrison strike sinks Owls and sends Whites three points clear of Blades

Leeds created a whole host of chances and after the Whites were continually thwarted by Owls keeper Keiren Westwood in the first half, Jack Harrison finally broke the deadlock in the 65th minute when volleying home a Pablo Hernandez cross.

The success saw the Whites tighten their grip on the Championship's second automatic promotion spot with just four games left with third-placed Sheffield United only drawing 1-1 with Millwall who bagged a 95th-minute equaliser at Bramall Lane.

Leeds were dealt a blow in the warm up as captain Liam Cooper became injured meaning Gaetano Berardi started at centre back with Luke Ayling becoming captain as Leif Davis took his place on the bench.

Aftet a hectic beginning, United were denied an opener in the 13th minute by a superb save from Owls 'keeper Westwood to tip a close-range header from Tyler Roberts from a corner over the bar.

But the Owls then squandered a brilliant opportunity five minutes later when Gary Hooper was played clean through but took too long to shoot and was eventually forced wide by Luke Ayling before firing into the side netting.

Leeds hit back as Gjanni Alioski fired over before a superb curling effort from the lively Roberts whistled inches wide of the right hand post.

But only great goalkeeping by Kiko Casilla then kept Leeds level as the Spaniard darted across his line to tip a fine effort from Barry Bannan around the post.

Chances were starting to pop up all over the place and Westwood again denied Leeds as he palmed a header from Harrison from an Ayling cross behind for a corner.

The corner eventually led to Ayling having a pop at goal which was desperately scrambled off the line by Hooper.

From another corner, Pontus Jansson then headed over the bar before Wednesday's Adam Reach volleyed well wide.

But Westwood once again saved the Owls in the 39th minute when denying Roberts at close range following a Patrick Bamford cross with Roberts then firing the rebound across goal and that proved the last opportunity of a frantic first half.

Leeds were then quick into their stride after the break with Jansson heading over from a corner before Bamford narrowly failed to slide in a Roberts cross with the striker heading the follow-up attempt wide.

Hernandez then fired a good attempt just over from the edge of the box before Roberts fired wide from a similar position.

Alioski then narrowly sent a fine long-shot over the bar before the Whites squandered another glorious chance through Bamford who scuffed the ball wide from a Harrison cutback.

It proved Bamford's last act with the striker then taken off for top scorer Kemar Roofe in the 64th minute and one minute later United were in front.

Hernandez yet again provided another valuable assist as the Spaniard delivered a fine cross from the right that was brilliantly volleyed into the bottom left corner by Harrison.

The Owls offered no response and Klich saw an effort blocked before Roberts fired over from the edge of the box.

Roofe then put a cross from Roberts into the net after substitute Adam Forshaw's touch but the striker had been flagged offside.

Two minutes later, Roofe then put a tame effort wide from a Forshaw cross on the counter.

But there were hearts in mouths in the 89th minute as a fierce Fernando Forestieri volley was blocked by Jansson before Marco Matias fired into the side netting.

Leeds, though, easily saw out four minutes of added time to take a firm grip of the second automatic promotion spot ahead of Good Friday's clash against Wigan Athletic at Elland Road.

Leeds United: Casilla, Alioski, Berardi, Jansson, Ayling, Phillips, Klich (Forshaw 76), Roberts, Harrison (Dallas 86), Hernandez, Bamford (Roofe 64). Subs not used: Peacock-Farrell, Davis, Shackleton, Clarke.

Sheffield Wednesday: Westwood, Palmer, Hector, Lees, Fox, Boyd, Hutchinson, Bannan, Reach (Matias 41), Fletcher (Nuhiu 76), Hooper (Forestieri 66). Subs not used. Dawson, Lazaar, Pelupessy, Winnall.

Referee: Tim Robinson.

Attendance: 36,461.