"We apologise to fans for the disruptions caused by this totally unacceptable behaviour."
The first invader had come on in the 22nd minute and had time to shake hands with Tottenham defender Jan Vertonghen and also take separate photos with Spurs stars Kyle Naughton and Erik Lamela before stewards finally intervened.
There was another invasion five minutes later, prompting an angry reaction from Tottenham striker Roberto Soldado, who tugged at the man's shirt.
When a third person came onto the pitch just before halftime wearing the same t-shirt, with the slogan 'Bassbud FC', as the two previous offenders, it added to speculation the problem was a coordinated effort and possibly some kind of publicity stunt.
The incidents are certain to provoke a UEFA investigation into Tottenham's security arrangements.
Tottenham's victory ensured them of a place in the knockout stages of the competition.
-AAP