Leinster head coach Leo Cullen praised the professionalism of his players after they booked their place in the quarter-finals of the Heineken Champions Cup with a 30-15 win against Ulster at the Aviva Stadium.

In dreadful weather conditions, the hosts outscored their opponents by three tries to two and Ross Byrne kicked 15 points off the tee, which kept a dogged Ulster side at arm's length for much of the second half.

The four-time champions never hit their free-flowing best across the 80 minutes but, with the game being played under steady rainfall and above a greasy pitch, Cullen was pleased with how his side navigated their way to victory.

"Happy to be through, I suppose, with lots of good stuff in terms of the intent in the performance," the Leinster coach told RTÉ Sport after the last-16 tie.

"Conditions made it very difficult, you'd be worried before the game it could turn into a bit of a lottery. There are things we talk about, in terms of pressurising the opposition, which is important.

"Overall, the lads managed field position well, some good variation in terms of play considering the conditions. But all it is is about getting through to the next round."

On another day Leinster could have won easily as they dominated possession and territory, particularly in the second half.

But they were made to graft hard for their three tries - scored by Ryan Baird, Jamison Gibson-Park and Andrew Porter - with Ulster logging 197 tackles across the 80 minutes.

"Ulster are a very, very good team and they made us work in a lot of facets," Cullen added.

"They dug in defensively really, really well, and made life difficult for us. How am I feeling now? It's looking ahead straight away, after such a long lead into this game, we have a short lead into the next game. A great challenge ahead."

Before the game, Dan McFarland had described Leinster as the toughest challenge in club rugby, and the Ulster head coach said the hosts "showed their class" with how they turned the game into an arm-wrestle.

"It's really disappointing," the Englishman said.

"It's an interpro, it's Europe, and we're out now. The lads put so much into that, and physically they put their bodies on the line today, but we came up against a great side. I thought they showed their class in difficult conditions today.

"We talked at half-time about the physicality, forcing errors from them. We needed to force errors from them to get a foothold in the game, but we also talked about discipline, and making sure that we didn't give penalties away to give them access, because they're so clinical.

"We didn't manage to do that in the second half, we still gave penalties away, whether it be at the set piece or around the offside line.

"Leinster are so good that if you give them access like that, they're going to score points, and sure enough they did."

Up next for Leinster is a repeat of last season's quarter final against Leicester Tigers but this time it will be at home, with the Aviva Stadium set to host their last-eight meeting over Easter weekend, on a date yet to be confirmed.

And Cullen says they'll have to find another gear this week if they're to hold off the English champions and return to the final four.

"I watched the game last night against Edinburgh, we played them at Welford Road at this stage last season, and they've a tonne of experience across their team.

"You see someone like Jasper Wiese made a real impact, their halfbacks, whoever plays, if it's Van Poortvliet or Ben Youngs [at scrum-half], Pollard at out-half. They'll fancy their chances of coming here, and for us it's trying to recover well now, put a plan together and try and do as much as we can with a limited amount of time we have next week, and hopefully we turn up here next week and get a big crowd again."

Caelan Doris and Garry Ringrose could come back into the Leinster side next weekend but Josh van der Flier may be a doubt after picking up and injury in the second half at the Aviva Stadium.

"We'll see," Cullen said on Van der Flier's status.

"I don't know the full extent of it. He seemed to be moving ok."