Joe Biden addressed supporters at a drive-in rally in Delaware at 12:40 am ET on Wednesday morning, as the presidential race remained too close to call and ballots remained uncounted in critical swing states like Pennsylvania, Michigan and Wisconsin.What they're saying: Biden said that his campaign believes they are "on track to win this election," but stressed that "it ain't over until every vote is counted, every ballot is counted.""Look, we could know the results as early as tomorrow morning. But it may take a little longer, as I've said all along," he continued."It's not my place or Donald Trump's place to declare who's won this election. That's the decision of the American people. But I'm optimistic about this outcome." The other side: President Trump quickly responded on Twitter, baselessly accusing Biden of trying to "steal" the election and claiming "a big WIN."Within minutes, Twitter added a label to Trump's tweet that read: "Some or all of the content shared in this Tweet is disputed and might be misleading about an election or other civic process."Trump added in a second tweet that he will be making a statement later Wednesday morning.The bottom line: The dueling statements previewed what is likely to come: Trump could seek to declare himself the winner prematurely and stop mail-in ballots from being counted in states like Pennsylvania. The dispute could end up in court.Go deeper: Trump's plan to declare premature victory