Luis Suarez showed "phenomenal" strength to recover from biting bans to become a Barcelona star, according to former Liverpool team-mate Charlie Adam.
Suarez has won 13 major trophies with Barca since moving from Liverpool in 2014, including the treble of La Liga, the Copa del Rey and the Champions League in his first season in Spain.
The Uruguay star secured a switch to Camp Nou after a stunning campaign in the Premier League in 2013-14, in which he scored 31 goals in 33 league games to win the European Golden Shoe and be crowned the PFA Players' Player of the Year and the Premier League Player of the Season.
Suarez could not make his Barca debut until October 25, though, after he was banned for four months by FIFA for biting Giorgio Chiellini at the World Cup.
It was the third time in his career Suarez was found guilty of the offence, the player having bitten Otman Bakkal while playing for Ajax in 2010 and then Branislav Ivanovic of Chelsea three years later, which saw him given a 10-game ban.
Adam, who was a team-mate of Suarez in his first season at Liverpool in 2011-12, says the way the forward has kicked on in his career is remarkable.
"He will have been disappointed at what had happened [his ban for biting], how he got involved in the situation, both situations, and how it occurred," Adam told Stats Perform.
"But the way he's bounced back from that mental toughness has been incredible. I still say he's one of the best number nines in the world where he could occupy a defence on his own.
"He's hungry to score goals, he's playing for one of the best teams in the world with the greatest player I've ever seen [Lionel Messi]. It's phenomenal to see that he's made that step up.
"It was crucial for him when he left Liverpool to go to Barcelona and everyone thought 'was he the right type of player for Barcelona?' but he's been phenomenal and I was grateful to be able to share the dressing room with him."
Adam has been hugely impressed with the link-up between Messi and Suarez at Barca, which has yielded four Liga titles in the past five seasons.
"The top players connect well. Even when Neymar was there, the three of them seemed to connect," said the Reading man. "There was no ego about any of the players, they wanted the best for the team and that's the important thing.
"You sort of saw it when they signed [Ousmane] Dembele. He was the other type of player that was all about him. When you're at Barcelona it's all only about one person and that's Lionel Messi. It's not being disrespectful, but you have to try and manipulate your game to suit him because he's the main man. But Dembele's not really gone there and expressed how Neymar did.
"Neymar knew that he wasn't going to be the main man at that time, but he got his head down, knuckled down and they had some great success together, the three of them."
Adam moved to Stoke City in 2012, where he played alongside former Barcelona forward Bojan Krkic and ex-Real Madrid man Jese Rodriguez.
Neither player was able to fulfil their promise with the Potters, with Bojan – whose best run of form was interrupted by a serious injury – now playing under Thierry Henry at MLS side Montreal Impact and Jese back with Sporting CP in Portugal, on loan from Paris Saint-Germain.
"Bojan was a player who came with the pedigree of where he'd played, Barcelona, he'd been at Roma and he'd been somewhere else [Ajax], and then he came to Stoke. And from day one he just hit the ground running, he was phenomenal," Adam recalled.
"On day one, you could see the talent he had. But most of all, he was a great guy. He was a great guy to have in the dressing room, always laughing and joking. But his mentality to work hard was incredible.
"The only thing about Bojan was when he got that knee injury, that was when his football went a different way. He had to change and adapt his game, he wasn't as sharp as he was but [he was] a phenomenal player.
"It's a shame to see an injury like that curtail someone's career because he could have been phenomenal for Stoke. I loved playing with him, I was playing that night against Rochdale [in an FA Cup match in January 2015] when he did his cruciate [ligament] and it was heartbreaking for the lads to see it because in the dressing room he was a great guy and it was disappointing for him.
"Jese was one where he came to the club from Real Madrid, he was the boy wonder at Real Madrid. He got that serious knee injury from that tackle with [Sead] Kolasinac [for Madrid against Schalke in 2014] and he ended up with a cruciate injury as well.
"He probably never fulfilled the potential or the career that he was going to have before that injury and that's what serious injuries do to you. For Jese, I think there was a lot of other things going on off the pitch, which probably never helped, and that was difficult.
"It was a strange one but, as a group of players, you've got to adapt and you've got to try your best but unfortunately, it never worked out for him."