Warner has been competing for the job with high-priced rookie Eli Manning, who played terribly Friday night in the Giants' 17-10 loss to the New York Jets.
Warner, a two-time former NFL MVP, signed a free agent contract on June 2. He is 35-15 as a regular-season NFL starter for a winning percentage of .700. That is the highest among active quarterbacks with at least 50 starts.
"That was goal number one coming in, to be the starter and help this team win a championship," Warner said.
Manning, obtained by the Giants on draft day when he was the No. 1 overall pick, signed a huge contract last month and got a $20 million signing bonus.
Against the Jets, he was a paltry 4-of-14 for 20 yards with two interceptions, and also had a fumble returned for a touchdown.