The Giallorossi saw their unbeaten run this season come to an end in a 3-0 reverse at Serie A leaders Juventus on Sunday.
The result was a blow in the race for the scudetto as it left second-placed Roma eight points behind Juve.
"We have a Coppa Italia match against Samp to play on Thursday and we must focus on that," Garcia said to www.asroma.it.
"We have to push on and get back to winning ways as quickly as possible.
"Have our Scudetto hopes now gone up in smoke? There are another 60 points to play for before the season is out so the league is not over.
"We are disappointed but have to use that feeling to motivate us to start winning again immediately.
"I have no doubt we'll do that against Sampdoria because I have 100 per cent trust in all of my players."
Samp also go into the encounter at the Stadio Olimpico on the back of a defeat.
The Blucerchiati fell 2-0 at Napoli on Monday as Sinisa Mihajlovic suffered his first defeat since taking over Sampdoria in November.
Fiorentina take on Chievo at the Artemio Franchi stadium on Wednesday without top scorer Giuseppe Rossi.
Rossi hurt his right knee in Sunday's 1-0 defeat to Livorno and will travel to the United States to see a specialist later this week in order to confirm the extent of the injury.
Reports in Italy claim that Rossi, who has had two previous operations to reconstruct cruciate ligaments in that knee, could be sidelined for at least three months.
Chievo, meanwhile, began the year with a goalless draw against Cagliari.
Udinese and Inter Milan will square off at the Friuli stadium on Thursday with both sides heading into the encounter on the back of defeats.
Inter lost ground in their chase for Champions League football next season after falling 1-0 at Lazio on Monday evening.
The outcome dropped the Nerazzurri to sixth place in Serie A, eight points behind Napoli, who are third and hold the last Champions League qualifying spot.
Udinese lost 3-1 at home to Hellas Verona to fall to 13th position.
The Friuli outfit, coached by Francesco Guidolin, have endured a frustrating campaign with just six wins in 18 Serie A games.
Next week, Catania host Siena, AC Milan take on Serie B side Spezia, Atalanta visit Napoli and holders Lazio welcome Parma to the Stadio Olimpico.