"He is a different player now to the one he was in Spain. He was so talented anyway but, physically and technically, he has adapted to the English game - and he is still improving," Antic told BBC Sport.
Liverpool will need Torres at his best if they are to get past Arsenal in the quarter-finals, starting with the first leg at the Emirates Stadium on Wednesday.
The Gunners kept him quiet when they fought out a 1-1 draw at Anfield in the Premier League in October, but Torres was not in full flow, limping off injured at half-time, and BBC Sport pundit Alan Hansen says stopping him again will not be so easy.
"Just because someone has got the better of Torres once does not mean they will do it again," Hansen said.
"He possesses such quality that it is difficult to subdue him every time.
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Torres is surprised by the speed of his Anfield success
"If you are going to defend with any degree of success against him, first of all you have got to be good - and it helps if you are quick because Torres is like lightning.
"The times when he has been most successful for Liverpool this season has been when defenders are square with him and he hits it past them.
There is nowhere for the defenders to go. If you don't get the ball first time he is away and you are either lost or you have to bring him down.
"You simply can't turn quick enough because he's got so much pace, which just about leaves you with one option if you don't get that ball, which is to foul him."
Few expected so much, so soon, from Torres but Antic, who was in charge at Atletico when Torres came through the ranks at the Vicente Calderón Stadium, always believed he would have an instant impact in England.
"I am not surprised," Antic said. "He is a special player and what makes him so special is that he has everything together - his game is very exciting and he is skilful and intelligent.
"He is always thinking about the way he can score goals. His character is not to be a loser, he is a man who wants to win.
Full name: Fernando Jose Torres Sanz
Born: 20 March 1984 in Madrid
Liverpool games: 34+4 goals: 28
Atletico games: 200+14 goals: 84
Spain games: 42 goals: 14
"It is also evident that he is enjoying himself, which is very important to him. In his last two or three seasons at Atletico he was frustrated - he was captain and the team was not doing well. Now he is happy again."
Spanish TV pundit and former Reds midfielder Michael Robinson agrees that Torres already seems at home at Anfield.
Robinson met Torres at the beginning of March and says: "The way Fernando speaks, you would think he was born in Toxteth.
"What stood out for me is how he is totally enamoured with Liverpool. He knows very clearly what Liverpool are about and what their principles are.
"When a team loses, a player might first think of himself. Fernando told me that when Liverpool lose, the first thought of the players is with the fans."
Liverpool's style of play under Benitez is another reason why Torres has thrived.
"Counter-attacking is very important for Liverpool and Torres is brilliant at this," Robinson explained. "He is supremely fast and a lethal finisher.
"Because Liverpool sit quite deep and hit on the counter, Torres has a lot of space in front of him when he gets the ball.
"He can utilise his supreme pace and midfielders don't have to be quite as accurate to hit him."
Benitez's tactics have helped Torres, who scored the winner in Sunday's Merseyside derby win over Everton, become the first Liverpool player to score 20 goals in a season since Robbie Fowler in 1995.
Torres has taken the Premier League by storm in his first season
His scoring rate is prolific, yet Antic believes there could be more to come.
"Liverpool can still get more out of him," Antic added. "He is also a good finisher inside the penalty area too.
"If Liverpool were to play a little more football, and get the ball in the box from wide positions, he would probably be even more successful.
"He is a player that needs good balls at the right moments but Liverpool do not dominate games. They play a little bit more defensively and do not dictate the pace of games."
One question mark over Torres is indeed about where he scores his goals.
But it is not about whether they have come from inside or outside the penalty area - more why they have not come more often away from Anfield.
Of his 21 so far in the league, 19 have come on home turf with 15 of those coming in front of the Kop.
Hansen, however, is confident that things will even themselves out sooner rather than later.
"If Torres starts scoring goals against the big teams away from home, then Liverpool will really be flying," Hansen said.
"This will surely happen because no-one can dispute his quality. He and Liverpool will feel a good place to start is in a Champions League quarter-final against Arsenal at The Emirates."
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