Lampard won two Premier League titles, the FA Cup and two League Cups under Mourinho as a player with Chelsea, but will meet him for the first time as a manager during tonight's third-round trip to Old Trafford.
Mourinho was widely regarded as one of the world's best managers during his time at Stamford Bridge, and subsequently with the likes of Inter Milan and Real Madrid, but questions over his effectiveness have been raised since his arrival at United.
However, Lampard still believes that the Portuguese - who proclaimed himself 'the Special One' during his opening press conference as Chelsea boss - has plenty left to give.
"I saw it and I liked it – I liked the confidence of it. It's not part of British culture to walk in [to a big club] and call yourself the Special One, but that's the way he was and I admired him for it. If you make those statements you had better back them up, and he certainly did, so fair play. He'd had huge success the year before at Porto and I'd heard about his dossiers, about Plan A, Plan B and Plan C. I was slightly nervous because you wonder 'am I going to be in Plan A?'" Lampard told reporters.
"I remember him coming up to the Lowry hotel in Manchester to meet the Chelsea boys on international duty with the England squad before the Euro 2004 finals. You talk about aura and personality when somebody walks into a room – his confidence struck me. Looking back, that's when I probably thought we were going to be winners. When he came to Chelsea, particularly the first time, a lot of us were hungry to win things.
"He brought a confidence that we will win and should win – he told us regularly and we started to believe it. The uplift was mainly psychological but Chelsea became a winning club and he was the driving force.
"United came second last season. Tottenham were a fair way behind and everyone agrees Mauricio Pochettino's a great manager, Liverpool were behind them in the League and Jurgen Klopp's a great manager. This is not ancient history, this is fresh history. In terms of still being the Special One, those are just words – in terms of still being a great manager, of course he is."
Mourinho won the Community Shield, EFL Cup and Europa League during his debut season with United, but endured a trophiless campaign last term.