Alexander Zverev knows how to correct unforced errors.

During Team Europe's pre-Laver Cup presser in Chicago, Zverev referred to the team competition as "an exhibition" then quickly corrected his slip of the tongue.

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"So that's why I think this exhibition—no not exhibition—this whole tournament, is so exciting for all of us," Zverev said.

Technically, the Laver Cup is an exhibition event as no ATP ranking points are awarded.

However players who competed in the inaugural Laver Cup at the O2 Arena in Prague last year, say the competitive intensity can match a Tour-level event.

"Honestly, that question really annoys me," said John Isner during Team World's press conference. "One-hundred percent serious. This is not an exhibition at all. At all."

Photo credit: Christopher Levy