Donald Trump tried to put the Republican convention back on track following a rank-and-file revolt Monday, telling party delegates "we're going to win" the White House.

Making a surprise cameo appearance at the gathering in Cleveland to introduce his wife Melania, the bombastic tycoon showed confidence that belied the day's spasm of public division.

"We're going to win so big" said Trump. "Ladies and gentlemen, it is my great honor to present the next First Lady of the United States."

Trump, who broke with tradition by appearing at the convention before his nomination, was addressing an audience that hours earlier erupted into jeers and yelling as anti-Trump Republicans insisted their voice be heard.

Many are furious that the party of Abraham Lincoln and Theodore Roosevelt will be led by a man who described Mexicans as rapists and advocated barring Muslims from entering the country.

"We deserve to be heard, this is the people's convention!" said Diana Shores, a delegate from Virginia, while pro-Trump delegates tried to drown out the rebels with shouts of "Shame! Shame!"

Trump fans insist delegates should heed the will of the grassroots of the party and make him the Republican nominee without equivocation.

The billionaire won a thumping victory in a series of statewide party elections, garnering more than 13 million votes -- the most of any Republican nominee ever.

This was meant to be Trump's moment -- the point at which he put the lid on Republican divisions and marched the party toward November's election and the White House.

- First the lady -
Ahead of the convention he had tried to assuage conservative critics and bring the party together by naming Indiana Governor Mike Pence as his running mate.

But it was Trump's Slovenian-born wife Melania who stepped up as his chief advocate on the convention's opening day.

She took the stage with all the allure of a former model and in a strong accent made the case for Americans to entrust Trump with the presidency.

"Donald is, and always has been, an amazing leader," said the 46-year-old. "Now, he will go to work for you."

"He does not give up," she said of her husband during an eloquent 14-minute speech in which she portrayed him as a loving father and successful businessman who would be a strong and compassionate president.

"If you want someone to fight for you and your country, I can assure you, he's the guy," she said.

She also sought to put a more human face on a candidate many voters see as brash and egotistical.

"Donald intends to represent all the people, not just some of the people. That includes Christians and Jews and Muslims. It includes Hispanics and African-Americans and Asians and the poor and the middle class."

After his wife, the candidate's team will send his son and daughters to the convention stage in the coming days.

- No-shows -
But in a sign of lingering party divisions, several party luminaries are staying away from Cleveland, including the entire Bush family, Mitt Romney and even John Kasich, host state Ohio's sitting governor who was visiting Cleveland but not the convention.

Much now rides on Trump and his supporters focusing on issues that unite Republicans: support for the armed forces and concern about law and order

Amid a spate of racially charged killings in the United States and terror attacks across the globe, Republican Congressman Michael McCaul summed up a core tenet of Trump's appeal: "Are you safer than you were eight years ago?"

But the Trump card may be hatred of the presumptive Democratic nominee Hillary Clinton.

On several occasions the convention broke into chants of "lock her up, lock her up."

Clinton fired back, blasting Trump's candidacy as a "threat to our democracy," and accusing him of stoking racial and ethnic tensions with his rhetoric.

Trump "plays coy with white supremacists, Donald Trump insults Mexican immigrants," she told the NAACP, America's largest black civil rights organization, at a meeting in Cincinnati.

"Donald Trump cannot become president of the United States," she said, to huge applause.

The Republican convention ends Thursday with a speech from the 70-year-old billionaire real estate mogul. The Democrats stage their own convention next week in Philadelphia.