Concerns have been expressed about major sporting events being held this year.
Rangers star Ianis Hagi insists they fear no one in the last 16 of the Europa League.
A 1-0 win over Braga in Portugal ensured progress for the Ibrox side.
The Rangers manager says his side only have "a small advantage" in the second leg.
The Ibrox side came from 2-0 down to win 3-2 in the first leg of their tie.
Fraser Forster saved a penalty to ensure the sides are level ahead of next week's decider.
The Glasgow clubs will experience VAR for the first time in the Europa League last 32.
Celtic have made more than £24m of profit for the season so far.