The challenge for Manchester United's crown looks set to go down to the wire this term, with Chelsea occupying top spot, a point ahead of their rivals.
The Blues have three remaining games, starting with Sunday's showdown with Stoke at Stamford Bridge and continuing at Liverpool before concluding at home against Wigan.
Deco has declared it is time to seize the opportunity.
"The first thing we need to know is that we are first," he told the club's official website.
"The last three games will be difficult and of course there is pressure in our minds because we need to win our games if Man Utd win theirs.
"It is a war and we need to be prepared, but if you said on the first day of the Premier League in August we would be one point clear with three games to go, two at home and one game away, we would all say 'okay, we'll sign'!
"This is okay. It would be better if we won or Man Utd lost on the weekend, but that didn't happen.
"Now our moment is here - we have three games and we need to play well and be together."
Chelsea's title hopes suffered a major setback with Saturday's 2-1 defeat by Tottenham.
Deco, whose return to the side in the past month has coincided with a run of five straight wins until last weekend, dismisses the significance of the result.
"We knew at 2-0 we could score. We tried and had chances but didn't score. It was frustrating but we need to carry on," he said.
"I don't think we played a bad game - we didn't have a lot of luck - and we need to recognise they played well."