The Gunners set up a quarter-final clash against Watford at the Emirates Stadium after Olivier Giroud and Theo Walcott both scored twice at KC Stadium.
Elneny started his third game for the north London side as the Egypt international underlined his potential following his January move to The Emirates.
The 22-year-old took to Twitter on Wednesday morning to dedicate a message to his team-mates following their FA Cup success against Steve Bruce’s Hull side.
— Mohamed ELNeny (@ElNennyM) March 9, 2016
The midfielder moved to Arsenal in a £9m deal from Swiss champions Basel in January.
Elneny scored nine times in 142 games in all competitions during a four-year stay at Basel.
Arsenal are in third place in the Premier League table after a 2-2 draw with Tottenham at White Hart Lane on Saturday afternoon.
The Gunners are eight points behind Premier League leaders Leicester City.
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