To say that things got heated during the US Open last night would be quite the understatement.Naomi Osaka claimed her first grand slam title with a straight-sets victory over Serena Williams in a match that has been overshadowed by the American's furious argument with umpire Carlos Ramos.Serena Williams' coach, Patrick Mouratoglou was caught red-handed for a coaching violation which, at the time, caused some controversy in New York. Williams strongly denied the claims she had received coaching during the match. Her anger then led to a racket being smashed following a point shortly after and the subsequent fiery 'thief' argument.So what exactly did Mouratoglou do to trigger such events?A video has since emerged of the hand gesture Mouratoglou and as you can see in the footage below, the evidence is pretty compelling.Afterwards, even Mouratoglou admitted he was trying to pass on a message to the eventual runner-up.“Everybody does it - you all know it," he confessed.“There’s a rule, yes, but you don’t screw a Grand Slam final and make it the drama the way it was. It could have easily been avoided if there was psychology,’’ Serena's coach explained. 

Since the event, umpire Ramos, has been praised by many for his display of officiating and not giving in to the pressure of Williams. 

Others have sided with Williams for voicing her opinion so strongly which suggests the fall-out may rumble on for a little while yet.

“She felt she was insulted,’’ Mouratoglou added.

“Treated like a cheater. She felt completely humiliated. That’s why she reacted like that. Integrity is the most important thing to her.’’

Unfortunately for Osaka, it has completely overshadowed her maiden Grand Slam victory.