Bernie Sanders's best moment of the first Democratic presidential debate was also his first moment of the debate.

His opening statement, which ran two minutes and 12 seconds, was a boiled-down version of the much-longer speech about economic inequality that has been winning him support on the campaign trail for the last several months. Unlike his opponents on stage, Sanders wasted no time with pleasantries or personal biography. Instead, he launched right into what why he is running for president.

"I think most Americans understand that our country today faces a series of unprecedented crises," Sanders began. "The middle class of this country for the last 40 years has been disappearing, millions of Americans are working longer hours for lower wages and yet almost all of the new income and wealth being created is going to the top 1 percent."

Sanders went on to bash the Citizens United  Supreme Court ruling, calling the campaign finance system "corrupt" and insisting it is "undermining American democracy." He described climate change as "real [and] caused by human activity," adding: "We have a moral responsibility to transform our energy system."

He concluded with this: "What this campaign is about is whether we can mobilize our people to take back our government from a handful of billionaires."

The entire two-minute speech was delivered in the loud (and borderline angry) tones that have now become a Sanders's trademark. His face was locked somewhere between a frown and a grimace. Most importantly, his passion was evident. "He really believes in all of this," you could almost hear people thinking to themselves while watching the debate at home.

Unfortunately for Sanders, the debate didn't end after the candidates' opening statements. Sanders struggled to answer questions outside of his comfort zone — he was not so good on foreign policy — or to respond effectively to Hillary Clinton's surprising aggressiveness on his voting record on guns.

What Sanders proved Tuesday night is that he can give a hell of a speech with a message that strongly resonates with the Democratic base. Whether he can expand his issue portfolio out wide enough to compete with Clinton — or Joe Biden — remains to be seen.