Yousuf, who made a triumphant return to the Pakistan team with his 24th career century, said he rated his hundred very high as he was under lot of pressure to perform and prove himself.
"I was making a comeback to the Pakistan team after a while and I could feel the pressure of the situation. People expected me to score and I am happy I was able to reach my target by the will of Allah," Yousuf said from Galle.
Yousuf scored his first Test century against Sri Lanka on a demanding pitch playing his first match for Pakistan since mid last year.
Yousuf had defected to the rebel Indian cricket League last year citing problems with the selectors and former captain Shoaib Malik.
Ironically Malik was at the crease when Yousuf reached his century and was the first to congratulate him and also wipe the sweat off his brow.
Malik was replaced earlier this year by Younis Khan. "I am grateful to Allah that I achieved what I had in mind when I went into play the match. It was not an easy pitch but I am happy my runs put my team in a strong position that is what pleased me the best," Yousuf said.
"I don't want people to think that Yousuf is only playing because of his seniority and past record." Yousuf said he enjoyed the challenge of battling it out against the Sri Lankan bowlers in the hot and humid conditions on a track not easy for batting.
"This is what Test cricket is all about you have to perform in such conditions."
Yousuf was fined Rs 500,000 by the Pakistan Cricket Board for playing in an unauthorised league after he resigned from the ICL and made himself available for Pakistan selection.