Ferguson said on Thursday that he was proud of United's performance after they beat Ajax Amsterdam 2-0 in Stockholm to win the Europa League trophy for the first time and qualify for next season's elite Champions League club competition.
Twenty two people died and more than 100 were injured after a suicide bomb attack at the Manchester Arena where American pop singer Ariana Grande was holding a concert on Monday.
Speaking at an event in Glasgow to celebrate the 50th anniversary of Celtic becoming the first British team to win the European Cup in 1967, the Scot hailed Jose Mourinho's side.
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"I think United last night gave the city a lift and I think that was what it was about. We are all proud of them, it was a great achievement," Ferguson told Sky Sports News.
"I think, first of all, Manchester is a city like Glasgow, it is a working class city, we have fantastic people there and they will get together," he said.
"They will get together because there is a working class ethic about them and there is a great unity now in the city."
Ferguson, who is now 75, managed United for 27 years, winning 13 Premier League titles, two Champions League crowns, the FA Cup on five occasions and the League Cup four times.
(Writing by Ken Ferris; Editing by Greg Stutchbury)
