The 28-year-old scored City’s second goal as the Premier League champions beat Chelsea 3-2 to claim their first trophy of the season in the Community Shield at Villa Park on Sunday.
“Carlos has worked ever so hard in pre-season,” Platt said.
“Since he has come back in he has really attacked his work and not had one day off.
“His goal was one of those you can remember him doing two years ago.
“He ducks inside, he goes away from people. That’s what he’s been missing and it was there again.”
Mancini and Tévez fell out last September when the former West Ham United striker refused to come on as a second-half substitute in City’s 2-0 Champions League defeat by Bayern Munich.
The Argentine missed most of the campaign following the confrontation, before returning to Mancini’s first-team in March and scoring four goals as City won the Premier League title.
Platt believes both parties were guilty of making mistakes in their handling of the affair, and he is confident Tévez can excel at City this season.
“A lot was said and done last year. Everybody has got to hold their hands up and say mistakes were made,” he added.
“But what do you do? Carlos has still got two years left on his contract.
“He is a very good player and he is playing for Manchester City.
“It is not a case of putting water under the bridge, it is a case of saying we are all batting on the same wicket here and we go forward together.”
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