Injury worries over Vasilis Barkas, Mikey Johnston, Karamoko Dembele and Ismaila Soro emerged over the course of an evening when Celtic lacked the cutting edge necessary to earn a victory which their performance merited.
Greek international goalkeeper Barkas pulled up in the pre-match warm-up, his place taken at short notice by Scott Bain, while Johnston, Dembele and Soro all had their contributions curtailed by knocks sustained in a high tempo workout against their English Championship opponents.
With his personnel options already more limited than he would like ahead of the imminent start to Celtic’s competitive campaign, Postecoglou will be hoping for good news when the various strains are assessed by his medical staff in the coming days.
With the first leg of Celtic’s Champions League second qualifying round tie against Midtjylland less than a week away, the sense of urgency in their approach to this latest preparatory contest was wholly appropriate.
As Postecoglou looks to imprint his identity on the side, their intensity and sharp passing had Bristol City on the back foot right from the start.
Johnston was a real thorn in the side of the hosts’ defence as he linked up impressively down Celtic’s left with Greg Taylor and it would be especially frustrating for Postecoglou to see the 22-year-old winger’s evening cut short when he limped off to be replaced by Adam Mongtomery midway through the first half.
Before his departure, Johnston had carved out a first opportunity for Albian Ajeti to add to his tally of pre-season goals but the Swiss striker screwed his shot wide.
For all of Celtic’s dominance of possession and territory, however, it was Bristol City who came closest to a breakthrough before the break.
A corner from Matty James caught the Celtic defence flat-footed and when Kasey Palmer nodded the ball down, Andreas Weimann’s clipped shot struck the outside of Bain’s right hand post.
Celtic’s injury woes continued with Dembele’s departure, following a hefty challenge by Palmer, with Ewan Henderson taking over.
Ajeti came closer three minutes from the interval, forcing City goalkeeper Max O’Leary into his first save of note with a low angled drive.
Soro, who had ended the first half looking as if he was nursing a knock, did not reappear after the break and was replaced by Liam Shaw.
The second half was more evenly contested, although Celtic continued to look the more threatening side with captain Callum McGregor dictating operations from midfield in typically assured fashion. David Turnbull was denied by another smart stop from O’Leary but Celtic couldn’t find a way through.
Bristol City (4-4-2): O’Leary (Wyles-Richards 76), Simpson (Vyner 62), Baker (Moore 62), Atkinson (Pring 62), Dasilva (Nurse 62); Palmer (Massengo 62), King (Bakinson 62), James (Janneh 62) (Edwards 77), Pearson (O’Dowda 62); Weimann (Bell 62), Martin (Conway 62). Sub not used: Morton.
Celtic (4-2-3-1): Bain (Hazard 75), Ralston (Murray 58), Urhoghide, Welsh, Taylor (Hjelde 77); Soro (Shaw 46), McGregor; Dembele (Henderson 37), Turnbull (Robertson 77), Johnston (Montgomery 26); Ajeti (Moffat 77). Sub not used: Ntcham.