Australian tennis player Cash had been guessed by Davina McCall, but Ross had mocked her suggestion, insisting that it had to be McEnroe based on his fake Scottish accent, displaying a replica Wimbledon trophy and making reference to well-known McEnroe quote "you cannot be serious".
Ross even said he would eat one of Bagpipes' liquorice pipes if it turned out to be Cash shortly before he took his mask off, but when he saw that McCall had actually been right, he shouted out: "It doesn't make any sense!"
Cash laughed: "Yes it does," as he explained he had Scottish relatives.
He added of his terrible fake Scottish accent: "Apologies to everyone in Scotland. I had a lot of fun anyway."
Earlier in the episode after Bagpipes performed Teenage Dirtbag, Ross had said he was "100% certain I know who is in that tartan onesie."
One of the clues included Bagpipes talking about a "cheap trick" and Ross said: "They had the band Cheap Trick play at their 50th birthday. That is John McEnroe."
But Cash explained that there was a coincidence as his own favourite band was Cheap Trick.
Poodle and Bagpipes found themselves in the bottom two of tonight's fourth episode in the series, but the judges chose to save Poodle for another week after the sing off.
— The Masked Singer UK (@MaskedSingerUK) January 15, 2022
Cash joins three previously unmasked singers this series - Chandelier was first out and revealed as Heather Small, followed by Snow Leopard who turned out to be Gloria Hunniford, and last week Lionfish was unmasked as Will Young.
Ross was also convinced he knew Poodle's identity, working out that it could be singer Mika based on a clue about being "hazel, cerulean and ultra lilac" which he thought referred to the Grace Kelly song lyric "I could be brown I could be blue, I could be violet sky".
Other characters singing tonight were Traffic Cone, Panda and Rockhopper, who will perform next week with Poodle and the other four remaining contestants for the first time that they have all appeared in the same show.
Watch: Lionfish revealed to be Will Young on The Masked Singer