Norris has a 24-point lead over Piastri and Red Bull's four-time world champion Max Verstappen with two rounds remaining, including Saturday's sprint in Qatar and Sunday's main grand prix.
Verstappen has emerged as a serious threat after being 104 points behind Piastri at the end of August and winning in Las Vegas last weekend, when both McLarens were disqualified.
Asked by reporters at the Lusail circuit whether there had been any internal discussions about helping Norris at any stage, Piastri replied: "We've had a very brief discussion on it, and the answer is no.
"I'm still equal on points with Max and I've got a decent shot of still winning it if things go my way so, yeah, that's how we'll play."
Seven race wins each
Piastri and Norris have both won seven races this season and the team have said repeatedly that they remain on equal terms, despite the Australian's performance drop-off, and can fight freely for the title.
The pair have managed to remain on good terms within the team, a rare occurrence in Formula 1 when there has been so much at stake.
"I think there's still a chance, and it's played out that way a couple of times before," said the Australian, whose manager Mark Webber was involved in a four-way title battle in 2010 that ended up favouring Red Bull's Sebastian Vettel.
Vettel went into the final race of that season in Abu Dhabi third overall, 15 points off the lead and without having previously topped the standings.
The German had stated before the race that he would help Red Bull teammate Webber if necessary but ended up winning both race and title.
"I know it's not impossible," said Piastri, who could become the first Australian to take the title since Alan Jones in 1980. "Obviously I also know that it's a bit of an outside shot.
"I can't just rely on having a perfect final two weekends... I need other things to go my way, and I'm very aware of that.
"I'm just going to try and have the best weekends I can, which I try and do every weekend, and see what happens to everyone else."
Ferrari and Mercedes, while not fighting for the drivers' championship, are also in the battle for second place behind McLaren in the constructors' standings and could take points from any one of the individual contenders.
"Regardless of what the championship picture looks like for others, everyone is going out there to try and fight for wins and podiums," said Piastri.
"So I don't expect anyone to make life easy."