Amid a hostile atmosphere, Webber immediately pressed home the advantage but the Sharks scored only once more before the break, through Rohan Janse van Rensburg, as a stream of penalties kept Perpignan within touch.
The atmosphere here at the Stade Amie Geral is hostile to say the very least.
A South American soccer match is the nearest comparison. ??#SharkTime
— Sale Sharks? (@SaleSharksRugby) October 12, 2018
But after a tight start to the second half with the teams level at 19-19, Luke James went over and the floodgates opened for McGuigan to score twice more and seal his hat-trick, having initially been denied a third try moments earlier.
There was time for Genesis Mamea to cross for Perpignan in the final seconds, but it offered little consolation to incensed home fans.
In other news:
Watch the Heineken Champions Cup Final live on RugbyPass throughout Asia and Australia.