(Reuters) - Six consecutive wins, including back-to-back 6-0 triumphs in the league, might just have squashed doubts that Ange Postecoglou is the man to lead Celtic back to the summit of Scottish football.

But the first real test for the Australian tactician will come next Sunday, when the Bhoys face bitter rivals Rangers in the opening Old Firm clash of the season as Postecoglou looks to mark the card of the reigning Scottish Premiership champions.