Mark McCall backed the ‘incredible’ Billy Vunipola to inspire his young Saracens side ahead of their trip to Leicester Tigers in the Premiership.

The league leaders head to Welford Road on Sunday with around a dozen senior players unavailable through injury or Six Nations international duty.

But despite a tough fixture against the reigning champions, director of rugby McCall remains optimistic – especially with the experienced No.8 Vunipola leading from the front.

The 68-cap forward, 30, has been a familiar face in the England side since 2013 but was left out of new coach Steve Borthwick’s squad for the Six Nations.

And McCall, who fielded a young side in their dramatic 20-19 win against Bristol Bears in their last game, said: “Billy actually led the charge in the last 20 minutes in the Bristol game, he was incredible. I thought the team followed his lead.

“He's not playing international rugby but he cares a lot about the club and cares a lot about the younger players who are here and giving them the support that he got when he was a younger player as well.

“He was in training week last week, which is hard for him because there's a big international weekend. He's in training with a younger group of players.

“Billy wants to play for his country. I saw that disappointment in week one. But I must say, around the place, as time's going on, he's been unbelievable.”

As well as a clutch of international absences, Saracens are without Tom Woolstencroft and Duncan Taylor - who just miss out with injuries - while Theo McFarland, Elliot Daly and Callum Hunter-Hill are ruled out for longer periods.

McCall described Saracens’ next three games during the Six Nations as an “island” but was excited at the prospect of giving valuable minutes to his young guns.

“We've got a different kind of group to coach,” he said. “We had some difficult games in November with them. We played Bristol away, Northampton at home and Sale at home and we managed to get good performances in all those games.”

Saracens go into Sunday’s encounter with an eight-point cushion on Sale Sharks at the top of the Premiership while Leicester sit eighth – although just three points separate them and third-placed Exeter Chiefs.

Saracens have only lost one of their last 13 matches and will be looking for a repeat of their 51-18 victory over the Tigers in October.

“Going to Leicester is as hard as it comes really when you've got some of the players missing that we've got,” said McCall.

“But it's the kind of experience that I think in the long run will be really important for this group.”

Richard Wigglesworth’s side is bolstered by Ben Youngs, who was omitted by Borthwick when he announced his 26-man training squad ahead for the Round 3 clash with Wales.

Five Tigers were selected to train with England, including Ollie Chessum and Dan Cole, who will not be up for Sunday’s selection.

McCall added: “They'll be a little bit less affected than we are by the England squad announced.

“But it’s all the more exciting for our young group to go and test themselves at a really difficult place against a really strong team.”