Brendan Rodgers’ men were tipped to score a comfortable win over Kilmarnock in Scottish Premiership action on Sunday.
And Celtic did take the lead in the 33rd minute through Matt O’Riley and looked on course for victory until as late as the 75th minute.
Then Phillips turned a cross from Kilmarnock’s Brad Lyons past Celtic goalkeeper Joe Hart, before Matty Kennedy scored with three minutes left to record a famous win for the hosts.
The result ends Celtic’s unbeaten record in the Scottish Premiership this term and Bonner thinks the Bhoys missed Cameron Carter-Vickers.
He insists that with the way Kilmarnock played, Phillips looked edgy.
“It was about trying to play out through the press and I would always say Celtic are good at that”, Bonner said post match on BBC Radio Scotland.
“Maybe they miss Carter-Vickers, who’s got a wee bit more about him.
“Nat Phillips hasn’t played for a while, looked edgy especially under pressure from that perspective.”
Phillips is on loan at Celtic from Premier League giants Liverpool, but the Kilmarnock game was only his second 90 minute outing for the Bhoys in the Scottish Premiership.
