Roma are six-points above Rafael Benitez's men with a game a hand heading into the second versus third clash at Stadio San Paolo.
And Garcia believes the Naples outfit can ill afford to slip up when the two sides lock horns in a mouth-watering encounter.
"There are another 11 games after this for them, 12 for us, and we have a six-point advantage with a game in hand," he said.
"The pressure is on Napoli, as if they lose tomorrow then it's practically all over. If we lose, we'll still be in second place with a buffer. We are strong, so are they."
The game marks the fourth time this season the two have faced one another, following Napoli's 5-3 aggregate victory in the Coppa Italia - after Roma had won the first leg 3-2.
Garcia is hoping for another enthralling spectacle and the Frenchman is determined to come out on top.
He added: "I hope to see the same kind of spectacle that we had in the Coppa Italia semi-final first leg.
"So far this season we have played Napoli three times, winning twice. They have the second most prolific attack in Serie A, we have the third.
"Anything can happen and we must show, as we did after losing to Juventus in Serie A and beating them in the Coppa Italia, that we can win anyway.
"The best team wins, I hope to see a great game and we need everyone to be at 100 per cent for that to happen.
"The real problem in the Coppa against Napoli was distraction on set plays, so tomorrow we must be ready to make the most of those situations.
"Would a draw be acceptable? Of course, but if you play for a draw then you risk defeat. We must always play looking for the victory."
