Concerns were expressed by football pundits, who suggested that Boro's record £8.15 signing may struggle to settle in North East England.
However, Maccarone has made a massive impact, and McClaren has thanked Boksic for playing his part in helping the youngster.
"What has really impressed me the most is the way Alen helped Massimo in different ways," said McClaren.
"He [Maccarone] looks up to Alen because of his reputation and what he achieved in Italy, he's learning from him.
"Massimo has had a tremendous start, he was a firm fans' favourite with the fans from day one and rightly so - and some of that is due to Alen.
"Alen is a world-class talent, but his attitude has also been first class.
"He has accepted he has had to sit on the bench but has still been a big influence with all the younger players, not just Massimo."
Boksic has had an injury plagued pre-season and although fit enough to start the campaign, he has been forced to play from the bench with Slovakian Szilard Nemeth and Joseph Job taking their opportunities with both hands.
However, Nemeth has now picked up a hamstring injury and the Croatian should almost certainly start against Spurs - the club who were linked with a swoop for Boksic in the summer, something McClaren never took seriously.
"We never talked about Alen leaving and it never really reached that stage," said the Boro boss.
"We believed he was always coming back to us after the World Cup because he had the motivation to play here in the last year. He has been tremendous, he is a player who commands respect.
"The younger players learn from him just by training and playing, he doesn't always have to talk to them.
"That's been valuable, but I know he's chomping at the bit to come in and start."
Boro will bring back captain Gareth Southgate at Spurs, after he overcame a back injury - whilst Dutch international George Boateng could make a shock return after making an unexpected return to training on Thursday following a hamstring injury and a dose of flu.
