The double between the pairs Nicolas Mahut - Pierre-Hugues Herbert and Zdenek Kolar - Jiri Lehecka will therefore be decisive.
The first match was lost by Richard Gasquet (86th) against Tomas Machac (143rd) 7-6 (7/3), 6-2.
Great Britain, the third team in Group C, will compete against France on Saturday.
Mannarino broke in the first set to lead 4-2.
But while he was serving at 5-3, he in turn gave up his face-off, failing to convert a set point.
French Adrian Mannarino, against Czech Jiri Vesely, during their Davis Cup Group C match, November 25, 2021 in Insbruck JOE KLAMAR AFP
And the two players came to the tie break, easily won by the Czech who was very solid when the French passed by and did not score a single point on his serve.
In the second set, Mannarino managed a white break to break away 2-1.
He then held his face-off - not without saving several breaking points - to tie a set everywhere.
As in the first set, Mannarino missed a first set point, but this time he secured the second.
The French Adrian Mannarino, congratulated by his captain Sébastien Grosjean, after beating the Czech Jiri Vesely (6-7 (1/7), 6-4, 6-2), allowing France to equalize (1-1) against the Czech Republic in Group C of the Davis Cup, November 25, 2021 in Insbruck JOE KLAMAR AFP
Vesely saved four break points to finally win the endless first game of the deciding set.
But thereafter, Mannarino won five games in a row and served to conclude at 5-2.
He offered himself three match points and concluded at the net on his first.
© 2021 AFP