TAMPA (Reuters) - Republican U.S. Congressman Ron DeSantis came under fire on Wednesday when the President Trump-backed Florida gubernatorial candidate said his state should not “monkey this up” by electing Democratic Mayor Andrew Gillum, who is African-American.

Gillum scored a surprise victory in Tuesday’s Democratic primary for one the United States’ most competitive races for governor. If the 39-year-old Tallahassee mayor wins the Nov. 6 election, he would become the most populous U.S. swing state’s first black governor.

Critics on Wednesday blasted DeSantis, a staunch Donald Trump supporter who won his party’s nomination the previous day, for comments they said had racist undertones.

Interviewed on Fox News, DeSantis said, “The last thing we need to do is to monkey this up by trying to embrace a socialist agenda with huge tax increases,” after calling Gillum “an articulate” spokesman for far-left views.

Words like “monkey” or “ape” have been used to demean African-Americans and calling a black man “articulate” can be seen as racist.

However, in American colloquial speech, “monkey with” or “monkey around with” can mean handling something carelessly or incorrectly.

Gillum, however, told Fox News his opponent’s “monkey” remark “wasn’t lost on me. It’s very clear that Mr. DeSantis is taking a page directly from the campaign manual of Donald Trump,” who has been repeatedly criticized for remarks seen by some as racist or racially inflammatory.

Slideshow ( 4 images )

In an interview with Politico, Gillum said Florida would be “looking for a governor that was going to bring us together, not divide us. Not misogynists. Not racists. Not bigots.”

DeSantis spokesman Stephen Lawson said the 39-year-old candidate was referring to Gillum’s political positions, not his race.

“Ron DeSantis was obviously talking about Florida not making the wrong decision to embrace” Gillum’s policies, Lawson said in a statement. “To characterize it as anything else is absurd.”

At the White House, Trump told reporters he had not heard about DeSantis’ comments, and praised the Republican candidate as “extraordinary.” On Twitter earlier on Wednesday, the president slammed Gillum as a “failed” mayor, without citing examples.

The DeSantis-Gillum matchup will be closely watched for clues about the mood of voters and messaging ahead of 2020, when Trump could be seeking re-election against a liberal Democrat. Florida’s two major parties are now looking to their most fervent supporters - progressive Democrats and Republican conservatives - for victory in November.

On Tuesday, more than 3.5 million people voted out of 13 million registered Florida voters for a turnout rate of 27 percent, the highest for a non-presidential primary in the state since 2002.

DeSantis won his primary by touting his closeness to Trump.

Gillum won as an unabashed progressive who backed “Medicare for all,” impeaching Trump and standing up to the National Rifle Association. He said he hoped to motivate younger progressives and minority voters who often sit out non-presidential elections.

A victory would mark a change in fortunes for Florida Democrats, who have not held the governor’s office for 20 years, and have lost close races after nominating moderates who failed to generate enough enthusiasm, particularly among key minority voters. Just 48 percent of the state’s registered Democrats are white, according to state data. Florida’s registered Republicans are 83 percent white.