'Human nature' to try and protect lead - Cullen

Leinster head coach Leo Cullen said it was "human nature" that his side tried to protect a lead in their 20-17 Investec Champions Cup semi-final victory over Northampton.

In front of a competition record crowd of 82,300 in Croke Park, Leinster were 20-3 ahead early in the second half with James Lowe notching his third try of the game in the 43rd minute.

Saints would score the game's final 14 points, however, and the hosts were reliant on a late Jack Conan turnover to secure what became nervy passage to a fifth European final in seven seasons.

"The score goes to 20-3 pretty early in the second half, and then I suppose there's a human nature part to it," Cullen said.

Leinster had been dominant against the Premiership leaders in the first half, with Cullen adding that credit must go to Northampton for coming into the game after the turn.

"You can try and sit and protect what you have, that can be the real challenge," he added.

"Can you try and push on at that stage? We maybe struggled with that a little bit, but credit to Northampton as well. They dug in well defensively and made life tough for us.

"You're playing knock-out games, so the team that's behind is going to be doing everything in their power to come back into the game and make it as tight as possible.

"It's not like anyone thinks we're going to roll these guys over. Nobody is thinking that at any point. At 20-3, we're not thinking it.

"The most important thing is that you get over the line, and we managed to get over the line thankfully."

Leinster came into the game having rested their starting side for the two United Rugby Championship [URC] games in South Africa last month.

With three weeks before the final in Tottenham Hotspur Stadium on 25 May, Cullen said that those who beat the Saints would be back in league action before the decider.

Leinster have fallen to second in the URC with three games remaining, trailing Glasgow by four points.

"Listen, we've done enough to get through, we know we can be better, and that's the bit we have to go after over the next couple of weeks," Cullen said.

"We're back to URC action next week against Ospreys, and it's important that we focus our attention on that now.

"We need to give them the full respect next week."