Success scored his first goal of the season in the 36th minute to give Watford the lead at the Madjeski Stadium.
Watford scored their second through a powerful shot by Domingos Quina in the 62nd minute as they held on to progress to the next round of the competition.
The game marked Success first start for the Hornets since 2016, and he scored his first goal for the club since 2017 as he was sent on loan to Spanish side .
Speaking to the media after the game, Garcia stated that he was impressed with the work ethic of the Nigeria International.
He also revealed that upon Success performance against Reading that he can challenge the first choice attacking options Troy Deeney and Andre Gray.
Garcia said, “Today he (Success) has scored a good goal for the team.”
He also stated that he encouraged Success and his teammates who have not been getting much game time to prove themselves.
Garcia said, “I spoke with every player before the game and tried to explain that they don’t have to show anything different than they usually do in training, in pre-season.
“They are good professionals – the only thing that changed is the opportunity to play. It is very good for the group that they enjoy more minutes.”
Successwill aim to maintain his goalscoring form when Premier League leaders Tottenham Hotspur visit Vicarage Road to face Watford on Sunday, September 2.