The Barcelona assistant coach heralded his star man as he came off the bench to alter the Champions League quarter-final second leg against Paris Saint-Germain
Messi was involved in the build-up play to Pedro's equaliser as he darted in behind the Paris Saint-Germain midfield before finding David Villa, who laid the ball off to Pedro to fire home.
Roura stated it was always planned for the Argentina international to make an appearance if things were not working out and that his introduction changed the game.
"We agreed with him before the match that he would come on if things weren't going well. And that's what we did,” Roura told AS.
"He's such an important player that his presence affected the game. His introduction influenced our opponent. He showed his capacity to compete."
Roura, who was in temporary charge while Tito Villanova received treatment for cancer, was quick to praise the club for their consistency over recent seasons after they advanced on away goals, 3-3 on aggregate - creating a new record in the process.
"The team showed what they're made of. Reaching [a record] six consecutive Champions League semi-finals is a real achievement.”
Barcelona will face either arch-rivals Real Madrid, Bayern Munich or Borussia Dortmund in the last four of the competition.
The draw will be made on Friday in Nyon, Switzerland.