(REUTERS) - It was arguably the greatest comeback in Champions League history and one that very few people saw coming, as punters shied away from backing Barcelona to complete an extraordinary comeback against Paris Saint-Germain on Wednesday.

Only seven per cent of pre-match wagers backed Barca to overturn their 4-0 first leg deficit, according to William Hill, who had the Catalans at 33-1 to win the competition prior to Wednesday's extraordinary second leg.

With Barca scoring three times after the 88th minute to complete a 6-1 win on the night and a 6-5 aggregate victory over two legs, most of those who bet on the match were left disappointed.

Having drifted in play to 50-1 to qualify for the quarter-finals, Barca are now favourites to lift the trophy at 11-4.