Donncha O'Callaghan branded Munster's performance as "totally unacceptable" after the province came unstuck at Zebre in Saturday's United Rugby Championship clash.
Munster led by 13 points at half-time but ultimately succumbed to a 42-33 URC loss at the Stadio Sergio Lanfranchi in Parma against a Zebre side that propped up the URC table last season.
Speaking on RTÉ Sport, former Munster second row O'Callaghan expressed his frustration about the way Munster went about their task.
"You don't want to take away from the fact that Zebre were full quality for it but it was totally unacceptable from Munster," said the RTÉ rugby analyst.
"Their performance, as individuals, as a team, to go on the road, we know what Zebre are. They were bottom of the league last year, of course they have shoots to come about.
"But Munster's performance there was completely unacceptable."
O'Callaghan put the microscope over the unforced errors that undid Munster as the match wore on.
"The amount of errors, the amount of poor performances, the amount of individual sloppy mistakes was just totally unacceptable," he said.
"It is great for our league, it is brilliant to see Zebre coming on but Munster will look back on that and they should be embarrassed with that performance."
Also speaking on RTÉ Sport, former Ulster centre Darren Cave added that Zebre getting over the 40-point mark was almost unheard of and had not happened since January 2020.
"There were warning signs from last week," he added, referencing Munster's two-point win over Connacht in a high-scoring thriller at Thomond Park.
"That Munster defence, be it individually, they need to figure out a way to get organised quicker. It's as simple as that.
"We saw last week, players looking in, players not being set. (Donncha) and I were talking about it during the game. As a defence coach, if a team passes the ball five times to the edge and scores in the corner, it's not ideal but you can probably live with it.
"If you're a team that believes you can win trophies, it's just not good enough."
