Guzan reckons the Belgium international will offer a major obstacle when Aston Villa travel to Stamford Bridge in the Premier League on Saturday, looking to bounce back to form after being soundly beaten 3-0 at home by Arsenal.
Courtois has replaced Petr Cech between the posts for Chelsea this season after three years on loan at Atletico Madrid, where he won the Europa League, Super Cup, Copa del Rey and La Liga as well as playing in last season's Champions League final.
The 22-year-old used his move to Spain to raise his profile with consistently strong displays for Atletico in the last three seasons.
"He's someone who I believe is one of the top five goalkeepers in the world," Guzan said.
"Thibaut's resume is outstanding. His accolades for the past few seasons at Atletico speak for itself, with Belgium too.
"He's only 22 so these things are unbelievable. He's a top, top keeper and someone Chelsea sees their future with.
"There's nothing better that having the confidence of the manager and coaching staff.
"You want to be dependable and the guy the lads look to if an opposition player gets through the defence.
"You want them thinking that you're going to come up with the goods and make a save at the vital time. You want that responsibility.
"You relish that opportunity to be number one - be the guy that's going to hopefully help the team. That's what it's all about."
Guzan was back-up to Brad Friedel and Shay Given before eventually becoming first choice at Villa Park under Paul Lambert, and he can relate to the position Courtois was in after signing for Chelsea from Genk in 2011.
"It's a great feeling when you eventually establish yourself," he said.
"It's not easy being a goalkeeper because you have strikers trying to take your head off - and it's different from outfield positions in that only one can play.
"You have to wait for your chance, or even your half-chance. You have to take it because you don't know when the next one is coming around.
"Thibaut has gone to Spain, not knowing the language and league, and gone on to achieve individual and team accolades."
