Success joined the Hornets from Granada in 2016, signing a five-year deal with the club.
His career began with Spanish side Granada. Initially part of the Granada B squad, Success progressed into the first team, quickly becoming one of the most highly rates youngsters in Spain.
The forward, who can play in a central or wide attacking role, featured 56 times for the club scoring seven goals. A Nigerian Under-17 and Under-20 international, Success’ performances during the 2015/16 campaign also earned him the club’s Player of the Year award.
Success then agreed a five-year contract at Vicarage Road, completing a then club record transfer. He scored his first Watford goal in a 2-2 draw at home to AFC Bournemouth and made his senior debut for Nigeira in March 2017.
He spent the next season on loan at Málaga CF before returning to Watford for the 2018/19 campaign, during which he scored four goals in 13 starts in all competitions.
Injuries have since hindered his opportunities, but Success returned to end Watford's promotion-winning 2020/21 Championship campaign with a bang, scoring a late rocket in a 2-0 win against Swansea City – the final goal in the final game of the season.