Sarries meet the Welsh outfit in the Heineken Cup at Wembley on Saturday - and go into it after a hard-fought victory over the exiles at Vicarage Road.
"Ospreys beat Munster on the weekend and will offer a big challenge. But we have played six games at Wembley and won five of them, our players really enjoy their outings there, as do our supporters," said McCall.
McCall paid tribute to London Irish who took the game to their hosts with ambition and power.
"A lot of players put in a big shift for Irish out there and we had to defend well at times."
He added: "But we have a number of guys in the walking wounded at the moment and hope to have Brad Barritt and Charlie Hodgson back for the weekend, while Schalk Brits will have served his suspension."
Irish head coach Toby Booth admitted his team came up short in terms of taking chances, but called for more unity between officials when it comes to scrummaging.
Time and again, the props in action questioned decisions on the grounds of consistency, and Booth believes it is wrong to leave referees to cope with so complicated an area alone.
"We need all three officials to work better as a team of three because a referee alone cannot have eyes everywhere." said Booth.
"Right now, it's a bit like those numbers that come out on balls late on a Saturday night. I believe there is a degree of 'guesstimation' when it comes to scrums and who is in the right and the wrong.
"Referees have a difficult job there and should be supported all the time by their assistant referees."
Booth made no excuses over the game.
He said: "They are the champions, well drilled and well coached. You must take points when you get as close to their line as we did on a number of occasions.
"The difference between the teams was taking chances. We left their 22 too often empty handed. Saracens kicked all of their goals and left us with only one point to show for our efforts.
"Tom Homer deserves a mention because he was very sick all week yet insisted he wanted to play. By half-time he was running on empty.
"And three of the four locks out there are internationals, yet the outstanding lock was Matt Garvey whose carrying and all-round contribution make him the typical modern second row."
Owen Farrell was the match-winner for Saracens, kicking all five penalties he was presented with by referee Andrew Small.
Homer and Dan Bowden kicked penalties for Irish who also scored the game's only try when David Paice was driven over by his pack four minutes from time.
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