Paul Heckingbottom warned Sheffield United still have even more to give after they extended their lead at the top of the Sky Bet Championship table to three points with a 2-0 win at Preston.

Iliman Ndiaye and Oli McBurnie scored either side of half-time to clinch the Blades’ fourth win on the spin and help them move a further two points clear of Norwich, who could only draw 1-1 at home to West Brom.

Senegalese star Ndiaye broke the deadlock on 40 minutes in a first half that saw Ryan Lowe’s hosts, who went into the game having conceded just two goals in nine league games, enjoy sustained spells of possession and go close on several occasions.

Heckingbottom says he shook his side into gear at the interval and insists they still have plenty to improve on in the international break heading into a jam-packed October.

He said: “We wanted to be better in the second half than we were in the first. I think our goal woke us up, to be honest.

“We were lethargic in the first half and weren’t aggressive as we normally are. We were second to things and that’s what we needed to improve.

“All of them will be disappointed with the first half, but they were better in the second half.

“There were some people who applied themselves all the way through to the levels that we expect and what we want, but it wasn’t a lack of effort, it was more that we didn’t show the same intensity in the first half.

“The best part of the game for us in the first half was the last five minutes.

“We know we needed to be better in the second half and we were. We were strong in the end, it was a strong away performance.”

The Blades did start the brighter of the two sides as Rhian Brewster and Scotland international McBurnie both went close.

At the other end, midfielder Ben Whiteman let rip with a howitzer which flew over the crossbar before Ali McCann and Emil Riis Jakobsen also looked threatening.

Troy Parrott, on loan from Tottenham, had a right-foot shot deflected wide, but it was the visitors who scored first against the run of play when Ndiaye robbed Whiteman and kept his cool to lash home off the inside of the post.

And it was McBurnie who secured another welcome win on the road when he tapped in from close range directly in front of around 5,000 travelling Blades supporters.

The defeat leaves Preston, who remain with just two wins despite their impressive defensive record, in 15th place and three points off the play-off places.

Boss Lowe said: “The result was tough to take, but I thought we played some fantastic stuff.

“We got done from a long ball at the top end of the pitch. We don’t clear our lines and we leave it to a goalscorer, who finds a way to get it into the back of our net.

“We’re disappointed because we played a lot of good stuff against the leaders. Once again, we couldn’t find that ruthless edge.

“It’s a bit of a recurring theme when it comes to chances created.

“I’ve got belief, of course I have, that we will hit the back of the net, whatever way it comes.

“I think I need to instil a bit more belief into the lads and help us find that ruthless edge because, if the truth be told, I don’t think we have it at the moment.

“I’m not worried we’re not going to score because we’re creating chances, but it’s concerning we’re getting into good areas and we’re not finding the back of the net.”

The result marked Sheffield United’s second away-day triumph, and clean sheet, in a week after Reda Khadra’s dramatic late strike fired them to a 1-0 win at Swansea.

Dean Smith’s Norwich responded with a battling 3-2 victory over Bristol City but, after being held at home by the Baggies, Heckingbottom’s red-hot side are now three points clear at the summit heading into the two-week Championship hiatus.

The Blades boss added: “In the end it was a strong display.

“We try and take risks, but Preston were getting in behind us when we weren’t taking any risks.

“We know Ndiaye has those moments in him, but we were fortunate the Preston player thought he had time for an extra touch and we managed to score. It was a terrific goal.”