Mitt Romney clinched the Republican presidential nomination on Tuesday, May 29 with a resounding victory in Texas and now faces a five-month sprint to convince voters to trust him over Democratic President Barack Obama in the November 6 election, Reuters reported.

Although the race has been essentially over for weeks, Romney finally cleared the benchmark of 1,144 delegates needed to become the Republicans' presidential candidate after a long, bitter primary battle with a host of conservative rivals.

He will be formally nominated at the Republicans' convention in Florida in late August.

In a statement, Romney said he was humbled to win enough of Texas' 155 delegates to secure the nomination.

Romney's big day was overshadowed by his appearance with real estate tycoon and reality TV star Donald Trump, who organized a major fund-raiser for Romney in Las Vegas.