Munster dug out an excellent draw with Exeter Chiefs at a blustery Sandy Park on Saturday to start their pool with two precious away points and will look to back that up against another Premiership outfit, Gloucester, this weekend.
Van Graan will come face to face with a familiar face in Limerick, and he expects another serious arm wrestle.
“I’ve been following their progression over the last year since Johan Ackermann went there, a fellow South African,” he told RTÉ Sport’s Michael Corcoran.
“He’s doing very well. They’ve bought quite a few players in pre-season and they’re playing some very good rugby.
“We’re under no illusions about the quality of their side. It’s a European game, The margins for error are so small. It’s one score, or one penalty, or one moment. It’s a fascinating battle that awaits us on Saturday.”
It was pretty absorbing fare in Exeter too, while Gloucester marked their first game in Europe’s premier competition with a gutsy 19-14 win against reigning the Top 14 champs Castres.
“This is what Europe is all about. You need to win at home.
“There was a lot of mutual respect between the two sides.