Oli Burke admits he lost momentum and belief under Neil Lennon at Celtic.
The Scotland cap was brought in on loan from West Brom by Brendan Rodgers before he left for Leicester City mid-season.
That saw Lennon take charge of the side before going on to seal a domestic treble.
Burke barely featured following the change in manager - which sparked a scathing rant from West Brom’s sporting and technical director at the time Luke Dowling.
Dowling insisted the forward had been poorly treated and that no Baggies players would join Celtic again.
Lennon would hit back at the tirade, claiming "maybe in hindsight I was too good in treating him too well at times."
The public war of words ended Burke's time in Glasgow's east end on a sour note, the 24-year-old admits he did find it tough to get going under Lennon.
Burke, now with Millwall on loan from Sheffield United, told the South London Times : “Brendan was an unbelievable manager.
“I felt like I played some of my best bits of football under him. He was very helpful and wanted the best for you.
“For it to change and someone else come in at such a weird time of the season was different. People come and go from places and you have to adapt.
“It’s difficult when you have momentum and belief in the manager and squad. We still went on to do well under Neil Lennon.
“One of my favourite experiences was playing for Celtic. The atmosphere and everything there – in Scotland football is life and death. It is such a big club."
