Watford have announced Isaac Success has signed a new five-year contract, following head coach Javi Gracia in committing his future to the club.
Success became the club's record signing when he joined from Granada in 2016 for a fee reported to be around £12.5 million.
The Nigeria international has scored just two Premier League goals for the club, although he has been affected by various injuries.
And Watford have shown faith in the 22-year-old by handing him a new long-term contract at Vicarage Road the day after Gracia put pen to paper on a new four-and-a-half-year deal.
"This is a just reward for Isaac's continued hard work and application this season," said chairman and chief executive Scott Duxbury.
"We look forward to seeing him develop further over the coming years."
Success spent the second half of last season on loan at Malaga, failing to contribute any goals as they were relegated from LaLiga.