Hoping to put things right against Heineken Cup champions Leinster, the Dragons were on the receiving end of a backlash from Joe Schmidt's side - going down 31-10 in Dublin.
All RaboDirect Pro12 sides are feeling the pinch of their star names playing in the World Cup and Leinster are without as many as 14 players, while the Dragons are only deprived of five.
Four of those however - hooker Lloyd Burns, lock Luke Charteris and back-rows Toby Faletau and Dan Lydiate - are integral members of the Dragons pack and the quartet have been sorely missed.
Willis however has backed squad players such as Andrew Coombs and Hugo Ellis to seize their chance.
"It's never easy when the team loses its five best players," said Willis, who won five caps for New Zealand between 2001 and 2002.
"But it's not a situation that doesn't apply to everyone else and so you cannot make excuses and worry about those players now.
"It's the chance for some of the young and enthusiastic players to come in and stake their claim for a place in the team.
"And I've been impressed with the attitude of the younger players. They've come in and there are some good younger guys in our squad and they've impressed.
"It's a chance for them - and all of the team - to get hold of the jersey and try and keep hold of it even when the World Cup players come back."
While the Dragons ran into a Leinster side desperate to make up for their surprising opening day defeat and felt their full force, but against Munster, the Welsh side almost sprung a major surprise.
As Munster had three men sent to the sin bin throughout the match, Dragons found themselves 17-12 down in the closing stages and on course to at least leave Musgrave Park with a bonus point.
But a sloppy penalty was conceded and duly converted by Ian Keatley - and Willis believes mental toughness will be key to ensuring that doesn't happen again.
"We really felt like we left a bonus point out on the pitch against Munster," he added. "And Leinster are as ruthless and as relentless as they come in this league.
"I don't think we were mentally strong enough but that is something that we will continue to work on."
63x46.png){kind=logo}