I can't dwell on World Cup woe or I'll lose Leinster place, says Van der Flier
There have been times after previous World Cups when the internationals came back in and stank the provinces out.
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Understandably low after another quarter-final exit, the Ireland stars faced into another eight months of rugby with a sense of doom and gloom that took a couple of weeks to get out of their systems.
Four years ago, the hangover lasted a full season and none of Ireland's Champions Cup contenders got out of their pool.
At Leinster, that opened the door for a new generation of talent to emerge, and Josh van der Flier was part of the contingent who took full advantage.
Now, he's one of those Ireland players who has come back from Japan after yet another disappointing exit. But he knows that licking his wounds will only open the door for Scott Penny or Will Connors, who impressed when he was away.
And if he wasn't already aware of the need to perform, he was reminded of it within a few days of joining up with his club.
"It was one thing that Stuart (Lancaster) and Leo (Cullen) said to me when I came back, that basically it's expected that I'd have to perform because all the back-row are all playing well," the Ireland openside revealed.
"There's a lot more pressure on the position, but I suppose there always is."
The genial 26-year-old responded well against Benetton last weekend, laying on a try for Johnny Sexton in a performance that saw him make his customary 18 tackles but also carry for 46m in six attempts.
He enjoyed being back in blue and he's been impressed with some of the new faces who have stepped up while he was away.
"You look at Ronan Kelleher, who has been scoring tries every week," he said. "And at No.7, Will, Scott Penny, they've been incredible.
"It was one of the things watching the games, coming back from the World Cup, I was thinking over the last couple of weeks that if I don't train at my best or put in a really good performance when I can then I won't be playing, because the other lads would deserve it.
"Obviously they've got the club to the position we're in in the PRO14, so they've been incredible, and it really pushes us on."
Van der Flier was determined to flush the World Cup from his system straight away.
"The moment we'd come home from the World Cup, all I wanted to do was play because you always remember the last game and you don't want the last game, a loss, hanging over you," he said.
"It's normally a PRO14 game you come back in for, obviously there's a bit of pressure there, but Europe is a different level.
"I got two full weeks' training leading in and that helped a lot. I felt comfortable enough but obviously I was maybe a small bit rusty with some bits and pieces.
"It was good, there was a good flow to the game.
"I thought we attacked quite well and managed to find a bit of space, got a few carries in as well which was nice.
"It was just the way the game panned out."