Gueye is the first player to be sent off in the Premier League for fighting with a team-mate since Ricardo Fuller with Andy Griffin for Stoke in 2008 against West Ham.
Former assistant referee Darren Cann, who oversaw more than 1,000 professional matches, described the clash between Gueye and Keane as “unusual”.
Speaking to BBC Radio 5 Live, he added: “Tony Harrington was looking directly at the confrontation. He had an unobstructed view and clearly saw Gueye slap Keane around the face, so in the laws of football that would constitute to violent conduct and a red card is the right decision.
“We know this sort of thing has happened one or two times before, but it is still quite an unusual incident.”
Former Everton boss Roberto Martinez, speaking on Sky Sports, said he was “very surprised” at the clash.
“There is a bit of a misunderstanding between them,” added the Portugal boss.
“The referee has no choice, the law tells you that is red card.”
