David Saker questioned Steve Smith's decision to take the extra half hour on a gruelling fourth day of the first Test for Australia's bowlers in which Pakistan showed admirable resilience.
Australia needed eight wickets at the Gabba on Sunday to take a 1-0 lead with a day to spare, but Asad Shafiq made a magnificent 100 not out after Azhar Ali (71) and Younis Khan (65) had also dug in.
Mohammad Amir (48) and Wahab Riaz (30) gave great support to Shafiq, who was still there when Pakistan were 382-8 at stumps - needing another 108 runs to pull off the biggest successful run chase of all time.
Australia captain Smith, who dropped two catches, opted to stay in the middle and prolong a rain-affected day in the hope of sealing victory.
Assistant coach Saker was not convinced of the wisdom of Smith taking the extra time available after watching Shafiq claiming a Test-record ninth century batting at number six, bettering the legendary Garfield Sobers' tally.
"Actually I don't know what happened. It was a bit frustrating from where we were sitting," said Saker.
"We were quite happy to come off, as a support staff, because I thought we'd done quite a bit of work and we'd probably rather our fast bowlers put their feet up. We weren't sure what was going on.
"I know the umpires and Steve were talking out there. I haven't had the chance to talk to Steve about what happened. Obviously they've just given them the half hour extra, which is allowable.
"I suppose with an 'in' batter in, that probably wasn't the right decision. But a lot of people wanted the game to finish and the umpires are probably one of those."
Smith put Sarfraz Ahmed down before also giving Shafiq a lifeline on 72, much to the frustration of the Australia coaching staff.
Former England bowling coach Saker added: "He's obviously a very good slips fielder and he has dropped two catches that he'd usually catch,
"It was a bit frustrating in the dressing room as well. I think he wouldn't have wanted to have been in our rooms with Darren [head coach Lehmann] and I going off.
"But that's the way it is and that's cricket. He's usually a very safe pair of hands and then he ended up taking a pretty good one at the end, which is a pretty important wicket in the context of the game."