UPDATE 1-Tennis-Del Potro puts Argentina level with Czechs

* Czech Berdych beats Monaco in close match

* Del Potro levels for Argentina with easy win over Minar

* Czechs nominate Berdych to join Stepanek for doubles

(Adds Czech doubles nomination)

By Martin Dokoupil

OSTRAVA, Czech Republic, July 10 (Reuters) - Juan Martin Del Potro cruised past Ivo Minar in straight sets to put Argentina level at 1-1 with the Czech Republic in their Davis Cup World Group quarter-final on Friday.

Argentina, led by world number five Del Potro in the absence of the injured David Nalbandian, saw their chances improve after Czech Radek Stepanek was left out of Friday's singles due to a knee problem.

However, the Czechs took the lead in the tie when world number 20 Tomas Berdych overcame Juan Monaco 6-4 2-6 2-6 6-3 6-2 after three hours and 27 minutes in a tough opening match.

"I had problems with first serves. Then it improved and the last two sets were clear," Berdych said.