Unlike past presidential runs, Hillary Clinton has done well in avoiding clear mistakes while campaigning and during the first democratic debate.

Bernie Sanders had a momentous summer silencing notions that he was a fringe, unelectable candidate. But, as it currently stands, Sanders is still trailing Clinton by a decent margin as the primaries are fast approaching.

According to RealClear Politics, Bernie is lagging behind the democratic leader by 21.6 points nationally. Somewhat more concerning, Senator Sanders is 24 points behind in Iowa—the first caucus state.

Like most candidates, Sanders has been heavily campaigning in Iowa in an attempt to best Clinton in the first state to vote. Bernie’s team has been mobilized in Iowa, going door to door and making phone calls to residents in order to try to drum up support. Iowa is a vital battleground for both candidates since it can set the tone for many other states to follow suit.

In the past few weeks, Sanders has made it the mission of his campaign to separate himself from Hillary Clinton in ideological terms and in reference to past political stances and policy decisions.

During tomorrow’s debate, Sanders plans to focus on this distinction. He needs to make himself out as a clear alternative to Clinton for democratic voters. He aims to do this by focusing on the issues in which his and Hillary’s point of views don’t match up. In recent interviews, Bernie has expressed a strong desire to amplify these viewpoint disparities by heightening the fact that his stance on the issues have been rooted within his policies earlier and more directly than those of Clinton. He needs to use this fact to his advantage on Saturday in order to let the public know that he has been more loyal to progressivism than his Clinton counterpart.

Disregarding a slip-up, which Hillary has been keen on avoiding this time around, Bernie Sanders needs to have an out-of-the-park showing on Saturday to make up ground on Hillary as the primary vote stands nearer.

With Jim Webb and Lincoln Chafee out of the equation during this debate, the spotlight will be focused purely on Sanders and Clinton, as Martin O’Malley continues to have difficulty drumming up national support for his campaign.

Without a serious win over Clinton during this debate, Sanders’ chances of winning Iowa and the primary democratic election will continue to dwindle.

As a strong supporter of Bernie Sanders, I know he can do it. The debate Saturday is his opportunity, and seize it he must.