Donald Trump became the presumptive Republican nominee on Tuesday night after a decisive victory in the Indiana primary and his top rival in the presidential race, Senator Ted Cruz, suspended his campaign.

"It is a beautiful thing to watch, and a beautiful thing to behold," the former The Apprentice star said during a victory speech. "We are going to make America great again."

All of Indiana's 57 delegates were awarded to Trump. He won the primary with 53.3% of the vote compared to Cruz with 36.7% and John Kasich with 7.5%.

"We left it all on the field in Indiana," Cruz said in a speech. "We gave it everything we've got but the voters chose another path. So with a heavy heart but with boundless optimism for the long-term future of our nation, we are suspending our campaign."

Trump has yet to formally secure the 1,237 delegates he needs to win the Republican nomination, CNN reported, but now there is no serious opposition left to block his path since Cruz decided to drop out of the race.

Although the 2016 presidential campaign has been a vicious battle in which the Republican opponents often attacked one another, Trump took the high road after his Indiana victory and praised Cruz in a speech.

"All my life, I've been in competitions -- different competitions whether it's sports, business, or now, for 10 months, politics. And I have to tell you that I have met some of the most incredible competitors that I have ever competed against right here on the Republican party," Trump said.

"We started off with that 17 number and, just so you understand, Ted Cruz -- I don't know if he likes me or doesn't like me -- but he is one hell of a competitor. He is a tough, smart guy. And he has got an amazing future... So I want to congratulate Ted. I know how tough it is."

Trump managed to cut through a 17-person GOP field as opponents slammed him for making offensive, racist and sexist comments throughout his campaign.

Republican National Committee Chairman Reince Priebus tweeted Trump is now the presumptive nominee and therefore encouraged the party to "unite and focus on defeating" Democrat Hillary Clinton.