DONNCHA O’Callaghan has warned his Worcester Warriors team-mates they will be at risk of leaving Welford Road with a “scar on their careers” if they do not produce their “absolute best” against Leicester Tigers tomorrow (3pm).

Having won twice at Leicester with former club Munster, the giant lock has nothing but positive memories of the “intimidating” stadium.

But O’Callaghan also knows the dangers the Tigers pose and says Warriors, who lost 54-35 to Wasps in their last Aviva Premiership fixture, will need to improve to stop their opponents running riot.

“We were hugely disappointed with how we went and represented the group (against Wasps),” the 37-year-old said.

“But bodies have recovered and there will be no excuses if we do not produce our best at Leicester.

“It is almost disrespectful to say you look forward to going to Welford Road but you know it is going to challenge you.

“If you don’t bring your absolute best, you are going to get thumped out of the door.

“Even when you do bring your best, it can be really tough, so from a player’s point of view you can either get a scar on your career or get a great success.”

O’Callaghan, who has been dropped to the bench for tomorrow’s game, said the match against play-off hopefuls Leicester also provided a “launchpad” for 10th-placed Worcester as they look to push on next season.

“Leicester are European Champions Cup semi-finalists and flying high in the league,” he said.

“They are a benchmark team as they are everything that is good about rugby with their traditions and values.

“So when you play against teams like that, you can see where you really are and that is a big thing for us now.

“You can show that you can go to these world-class, intimidating stadiums and do something special.”

Since joining Warriors from Munster in the summer, O’Callaghan has been an integral figure in Dean Ryan’s team, making 21 appearances.

But the 94-cap Ireland legend admits the heartache of being sent off in Warriors’ 29-20 defeat to Leicester at Sixways in September still plays on his mind.

“It didn’t go well at all and for me to get two yellows is something I have carried with me for the rest of the season because I came in here trying to win the respect of my team-mates,” O’Callaghan said.

“To be honest, I think that (red card) was the single biggest reason we lost that match and that is a hard thing to carry with you, knowing you have let the lads down, especially a group who have emptied themselves.

“It was massively disappointing but today is a chance to put things right.”