Martin O'Neill has congratulated Celtic for their "phenomenal" triumph over Barcelona in midweek.
The former Bhoys boss, now in charge at Sunderland, watched every minute of the match where Barcelona were defeated 2-1 despite enjoying 88% of the possession.
O'Neill said: "I didn't realise until now that there was only something like 11% possession for Celtic so that is absolutely phenomenal to score two goals from that.
"I watched the game through and through and I thought it was just a magnificent effort by a great club.
"I saw Rod Stewart in tears, and it was a great, great effort - to beat Barcelona was fantastic."