January arrivals or not, Marcelo Bielsa is building Leeds United a midfielder fit for the Premier League present

The Leeds-born academy graduate stepped off the bench out of necessity with half an hour or so to go, Mateusz Klich having limped off.

When Bielsa sends Shackleton on, the end result is normally a good one, his record is fairly remarkable in that regard, winning 80.5 per cent of his 41 sub appearances.

Overall he has won 70 per cent of the 57 games he has played. To give that a little more context, none of the 33 players in club history with a higher win percentage have played more than 15 times for Leeds.

He has had the good fortune to break through under the manager with the highest win ratio, but in another sense he has been unlucky.

He might not trade any of those full-time celebrations as a used substitute for the world, but the presence of the ever-present Klich has prevented him from getting the starts his potential suggests he is worth.

In Klich, Bielsa has his ideal box-to-box midfielder, an attacking and defensive menace, one built from stern stuff, somehow maintaining fitness, despite the arduous tasks of his role, throughout Bielsa’s tenure without picking up injuries – until Tuesday night that is.

His thigh injury might just present a problem for Leeds and a chance for Shackleton, who, on recent evidence, is a more than adequate understudy.

He can play right-back – that’s where he featured when he replaced Klich against Burnley in the second half, with Stuart Dallas moving into the middle – but the midfield role he occupied at the Hawthorns is where his future most likely lies.

In the game against the Clarets, with Leeds having to defend so much, Shackleton had few chances to impress in possession but his quick feet did allow him to showcase a nice touch and turn that left Dale Stephens in his wake.

It was the kind of tidy control we have become used to seeing from Shackleton and the burst of breakneck speed that accompanies it allows him to spring into open space, where Leeds look most dangerous.

Beating Stephens high up the pitch allowed the Whites to unbalance Burnley and build an attack that could have sealed the game, had Pablo Hernandez found Patrick Bamford.

“He is a player with good organisation who is energetic, he is quick, he can surprise opponents,” said Bielsa on Tuesday.

Even if Shackleton can’t surprise his man, he is trustworthy in possession, keeps it simple and makes good choices.

Despite his tender age, youthful exuberance is only found in his energy and willingness and not in irresponsibility. He knows the importance of taking care of possession and in being where he needs to be.

That understanding was on display in his performance against the Baggies, although as Bielsa pointed out, ‘it took him a little longer to adapt to the game’ and there was an errant first touch and an uncharacteristic misplaced pass early on.

That pass came a minute after £29m Rodrigo gave the ball away. Even stars aren’t perfect.

Shackleton shook it off and went in search of the ball with just as much appetite and was functional, if not spectacular –although in this team, playing in this way, functional is sometimes spectacular enough.

He made a couple of nice recoveries, the second of which gave Leeds the ball ahead of their fifth and best goal.

Having won it deep in his own half, Shackleton fed Jack Harrison and moved forward, taking advantage of space in behind Conor Gallagher to make himself available for Dallas and when the Ulsterman found him, Shackleton played it back perfectly, first time.

It wasn’t just Shackleton’s touch, it was his little dart into space that pulled another defender out of place and gave Dallas time to find Raphinha, who curled in a beauty.

“As a box-to-box midfielder he defends with Phillips and attacks with Pablo,” said Bielsa.

“Sometimes he appears on the left of centre or the right, all in the same game. All those things at this level it is not easy to resolve but he is a player with character and he takes on the responsibility.”

This level, a level Klich took 30 years to reach, is the Premier League, where world class talent abides, but still Shackleton, 21, holds Bielsa’s trust.

Buying a midfielder should still be on the to-do list next summer, if the right one isn't suddenly available for the right price in January - Bielsa isn't expecting to make a signing yet knows Victor Orta is poised to take advantage of any opportunities that arise - but Leeds are building one at Thorp Arch fit for the present, never mind the future.