Saracens have tapped into the motivational powers of Ronny Deila's backroom assistant Jim McGuinness during their preparations for Saturday's European Champions Cup semi-final showdown against Clermont Auvergne.

Gaelic football guru McGuinness this week became the latest in a long line of sporting figures to address Saracens' first-team squad.

In the past, they have called upon the likes of American athlete Michael Johnson, former motor racing world champion Jackie Stewart and ex-England cricket captain Andrew Strauss, in addition to polar explorers and army generals.

McGuinness, 42, transformed Donegal into an All-Ireland champion team during his time in charge.

He guided them to three Ulster senior titles in four seasons, culminating with 2012 All Ireland silverware being secured for only a second time in more than 120 years.

McGuinness, a sports psychologist, also worked with Europe captain Paul McGinley during the Ryder Cup victory over the United States at Gleneagles last year, and he is part of Celtic's set-up under manager Ronny Deila.

"We bring speakers in on a regular basis," Saracens rugby director Mark McCall said.

"Jim McGuinness was the Donegal football manager for four seasons. He's currently the sports psychologist at Celtic and he was Paul McGinley's right-hand man at the Ryder Cup in 2014.

"When he took over at Donegal in 2010, they hadn't won a game for three seasons and hadn't won a championship for 19 seasons.

"He took them on a journey over four years and it seemed like a very similar journey to our own.

"He captivated the group for an hour. He is an extremely passionate speaker and he was fantastic for the players, who really enjoyed it.

"I am not from Donegal, but I studied the story from afar and admired what he did. He had a very interesting story."

Saracens will face a Clermont side in St Etienne that crushed reigning Aviva Premiership champions and quarter-final opponents Northampton 37-5 just 11 days ago, and they go into battle with their England lock George Kruis having agreed a new contract.

Guildford-born Kruis, 25, has signed what Saracens described as a "multi-year contract extension".

Kruis made his England debut against world champions New Zealand earlier this season and has won seven caps.

He is a Saracens academy product from the same group as players like Owen Farrell and Jamie George, and his new deal follows that agreed by second-row colleague Maro Itoje, whose fresh contract terms were announced on Tuesday.

"It's a big moment for me to sign on again and keep playing with the squad in the future," Kruis said.

"We have a great off-the-field ethos at Saracens, the club are very interested in player welfare and on the pitch we're in a great position in the league and in Europe.

"It was a no-brainer for me to extend my deal.

"You always want to get these things off your mind as soon as possible and it has been relatively pain-free for me. I am delighted to commit my future to Saracens."

And McCall said: "George has been at Saracens for a long time and is part of a core group of players who have progressed from the academy to establish themselves as key players at the club.

"He has been in phenomenal form this season for both club and country and his standing within the group has grown considerably.

"He is only going to get better and better as a player and we're excited to see him do that at Saracens."