Asmir Begovic believes that Gareth Bale has "grown a lot" since leaving Tottenham Hotspur to join Real Madrid last year.
The 25-year-old, who joined Los Blancos for a world-record transfer fee, has failed to score against Begovic in five previous attempts.
Despite this, the Bosnia-Herzegovina stopper is expecting a difficult 90 minutes this evening as he comes up against Welshman Bale once more on international duty.
"[Lionel] Messi and probably [Cristiano] Ronaldo are two of the best players in the world right now and I think that goes without saying," he told BBC Sport. "But people like Gareth Bale are working their way up.
"I think he's grown a lot since he's gone to Real Madrid from his days at Spurs. He's become a world-class player, almost, now. So he's a huge threat, but it's a great challenge and something that we relish."
Bosnia are looking to pick up their first win in Group B this evening, while Wales will be hoping to push on from their slender 2-1 victory over Andorra last time out.
