The former Celtic goalkeeper was left impressed by the imposing French defender.
Jullien, who signed from Ligue 1 side Toulouse this summer, was given his long-awaited Celtic competitive debut by Neil Lennon on Tuesday night.
The Frenchman helped his side keep a clean sheet in a 2-0 victory against Estonian champions Nomme Kalju.
He looked composed on the ball, dominating in defence and even like a real attacking danger at set-pieces.
Bonner believes he could be a big hit at Celtic Park, telling BBC Scotland: “What caught my eye was the performance of Christopher Jullien. I know Kalju got a few chances and Celtic got a little sloppy around the middle of the pitch but he showed all the qualities I would look for in a defender.
“He was talking, he was pushing the line up and he was taking control. He covered for Jozo Simunovic and stepped in to midfield with the ball. And a real threat in the box from set pieces.”
Jullien’s communication, as Bonner points out, was also a key feature of his performance and it bodes well for his time at Celtic that he is so comfortable dictating defensive organisation so early in his Hoops career.
He’s certainly not shy.
His leadership traits in defence are something that Celtic have arguably been lacking over the last few seasons.
His target will now be starting next week’s match away to Cluj in the third qualifying round of the UEFA Champions League, having to sit out this week’s domestic opener against St Johnstone because of suspension.
Celtic supporters had to wait a while for Jullien’s debut after he missed a large chunk of the squad’s pre-season, but now he is up to fitness he likely won’t miss many matches.
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