The west Londoners have enjoyed a successful festive period, responding to a 5-0 hiding by Manchester United to draw at Chelsea and Norwich before securing a last-gasp 2-1 victory against Arsenal Monday.
Fulham's recent performances have been a far cry from some of their earlier Premier League displays as they struggled to balance domestic and Europe League exertions.
Summer signing Ruiz believes the Cottagers are finally beginning to prove their mettle and predicts exciting times ahead.
"Arsenal was a really nice game to be involved in and I really enjoyed it," he told the club's official website.
"We knew we could turn it around against Arsenal because we were playing well, especially in the second half.
"We were keeping possession and creating chances and I knew if we scored then we could go on to win the match.
"When we won that match at the end it was great and I could tell how happy the supporters were. We all enjoyed the result.
"I think we're really getting to know each other on the field of play. When we play offensively I think we combine really well and defensively we're doing well.
"We have some very creative players and that's great for the team and I'm really enjoying it here at Fulham.
"I've always known about the two cup competitions that are played in England.
"I've heard about Charlton as a former Premier League team and we're expecting a tough game against them on Saturday."
Ruiz joined from Dutch side FC Twente in the summer for a reported fee of £10.6million.
Much was expected of the Costa Rica international following his move to England, although he took a couple of months to settle in at Craven Cottage.
Ruiz is now showing his true worth for Martin Jol's side but admits the recent festive fixtures were a shock to the system.
"To be honest I've never played two matches in the space of three days," he said.
"It's hard because we're playing at a very high level and all the teams are fighting very hard.
"We had one day's rest between Norwich and Arsenal but I can get used to that."