Celtic booked their place in the Europa League knockout stages on Tuesday night.
The Hoops booked their place in the last 32 of the Europa League despite losing 1-0 to Hein Vanhaezebrouck's side on Parkhead, as they finished third in Group B of the Champions League behind Bayern Munich and Paris Saint-Germain.
Celtic needed to avoid a defeat of three or more goals after beating the Belgian champions in their back yard in September 3-0, but were expected to put in a better performance on the night than last night's display.
Although it got the job done, Australian McDonald blasted his old side and claimed they were fortunate to progress as they came up against a side who have been struggling in front of goal with just 30 goals in 25 league and cup outings this term.
"You could tell Celtic were under no pressure to win the game. It was a jaded performance early on and there was no real movement. Anderlecht did a really good job in terms of keeping Celtic pressed high," McDonald said.
"I think they’d watched Motherwell in terms of that and how they frustrated Celtic at the back. Overall the first 45 minutes was very poor and you could see Brendan Rodgers animated on the touchline which you don’t see too often.
"Celtic were fortunate to come up against a side which has struggled to score goals this season, they were lacklustre in the final third as they didn’t got for the jugular."
The Hoops have gone one better than last season's Champions League campaign by qualifying for European football after Christmas despite managing to lose five out of their six games in Europe's elite competition.
Rodgers must settle his squad down and begin preparing for Saturday's trip to Neil Lennon's Hibernian at Easter Road, in what will be a difficult encounter against a side that have impressed in their first season back in the top flight.