It was the night of the underdogs in the U.S. primaries on Tuesday as Republican presidential candidate Ted Cruz and his Democratic counterpart Bernie Sanders both scored resounding victories over their respective parties' front-runners in Wisconsin.

Cruz added 33 new delegates to his pot after winning 48.3 percent of the vote while Donald Trump picked only three new delegates after taking 35.15 of the vote, as tabulated in Real Clear Politics. John Kasich, the third GOP candidate, registered 14 percent with no new delegates.

Trump now has a total of 740 delegates, needing 497 more to reach the 1,237-delegate threshold to clinch the Republican nomination. Cruz has a total of 514 delegates; Marco Rubio, who has quit the race, has 171 while Kasich has 143.

Despite Cruz's victory in Wisconsin, Trump still enjoys a sizable lead in the race for the Republican nomination.

If Trump maintains his current level of support in the remaining races, he could win a delegate majority before the convention, according to a New York Times analysis.

No other candidate has a realistic chance of capturing the delegates required to win the nomination outright. Even if Cruz were to win all of the remaining delegates, it is a near impossibility for him to reach the 1,237-delegate threshold, the Times said.

However, Trump is not yet assured of winning enough delegates to secure the Republican nomination, according to analysts. Reaching the 1,237-delegate threshold requires him to maintain the same level of voter support in the forthcoming races. Cruz and Kasich can still earn enough delegates between them to deny Trump a majority of the vote, thus forcing a second ballot at the Republican national convention where anything can happen, the analysts said.

In the Democratic race, Sanders won 45 new delegates after winning 56.4 percent of the vote. Hillary Clinton got 31 new delegates after taking 43.3 percent of the vote.

Clinton now has a total of 1,274 delegates while Sanders has 1,025.

Although Sanders won a large majority of delegates in the most recent contests on March 26 and April 5, he continues to trail Clinton by a large margin in the delegate count.

Clinton can win slightly less than half of the remaining vote and still earn a majority of the pledged delegates by June, the New York Times analysis said.

Cruz was ecstatic after the vote count. "What an incredible victory tonight," he told the crowd at his primary night rally in Milwaukee, Wisconsin, WND reports.

He said Wisconsin is a "turning point," adding that now, Americans "have a choice, a real choice."

"Three weeks ago, the media said Wisconsin was a perfect state for Donald Trump," Cruz said. "So just how significant is tonight? Well just today, our campaign has raised over $2 million. ... We've had over 1.3 million contributions.

"In the last two weeks, and in the coming days when Colorado and Wyoming finish voting, we are likely to have gained over 100 delegates on Donald Trump. ... I'm more and more convinced that our campaign is going to win the 1,237 delegates needed to win the nomination. Either before Cleveland or at the convention in Cleveland, we will win a majority of the delegates. And together, we will beat Hillary Clinton in November."

However, Cruz faces far more difficult contests ahead in New York, Maryland, Pennsylvania, Connecticut, Rhode Island and Delaware—states leaning on Trump.

But Cruz is undaunted. "Just a couple of weeks ago, all of the media commentators were saying Wisconsin was a state that I could not compete and do well," Cruz told supporters on Monday. "They were saying it was a state that was a natural state for Donald Trump ... and yet I think the people of Wisconsin, they're looking at the records of the candidates, and they recognise that Donald screams and yells a lot, but he has no solutions."