A new national poll released Tuesday afternoon, while Wisconsin voters were busy casting their ballots, shows Ted Cruz and Donald Trump in a statistical tie on the day of the Badger State primary.

Cruz, who could pull off an upset in the first GOP primary since March 22, draws 35.2 percent in the latest Reuters/Ipsos poll. The Texas senator is well within the survey's margin of error against Trump, who has 39.5 percent support.

A leaked internal Trump campaign memo cited the Reuters tracking poll as evidence the billionaire hadn't lost momentum after a bad week.

While the two leading GOP hopefuls are in a close race nationally, Tuesday's primary in Wisconsin could help Republicans determine whether they will indeed face a contested convention come July.

A big win for Trump would bring him that much closer to reaching the 1,237 delegate count needed to secure the Republican nomination. But if Cruz upsets the billionaire and pulls off a victory, Trump's chances of reaching that threshold become increasingly difficult.

Losing Wisconsin would also lend credence to speculation that Trump might be losing steam, as evidenced by his historically low favorability ratings and abysmal poll numbers among women voters.

The Reuters/Ipsos survey was conducted April 1-5 and contains a margin of error plus or minus 4.8 percentage points.