Roura - who is overseeing team matters as head coach Tito Vilanova continues to receive medical treatment in New York - said that Barcelona traditionally "don't do well" when Undiano takes charge of matters.
Undiano is already in the limelight after he was pilloried by a number of fans, former referees and former players for his controversial handling of the Champions League last-16 match first leg that saw Juventus win 3-0 at Celtic.
"There should have been penalties awarded for Celtic in my opinion," said former Juventus captain Gianluca Vialli.
Celtic have officially asked UEFA for clarification over Undiano's performance after he failed to issue a red card or penalty against the Italian champions despite several incidents of man-handling at corner-kicks and free-kicks by Juve defenders.
Roura said: "The referee is who he is and we do are not going assess the officials and whether they are good or bad.
"But there is evidence that our numbers with him are worse than they are with others, much lower. One fact is that the only league game we have lost is with this referee, and we have in memory the permissiveness that was the Copa del Rey final. It is a statistical issue.
"That said, we must wish him all the luck in the world and we certainly hope that his decisions do not mark the end of the game.
"What I have said is pure statistics, the whole world can see, I do not do reviews nor do I want to go into more detail. We know that these types of games are intense and much harder, but the limit should be there, in the lines of sportsmanship.
"I insist that we do not care about the referee, hopefully he will go unnoticed."