Douglas Harper's Etymology Dictionary
1970s, Spanish, literally "hand-to-hand."
Wiktionary
a. In close confrontation. adv. Characterized by head-to-head competition or conflict. n. A head-on conflict or direct competition; a duel.
Wikipedia
Mano a Mano is collaboration album from the singer-songwriters Luis Eduardo Aute and Silvio RodrÃguez from Spain and Cuba respectively.
Recorded live in Madrid (Plaza de Toros de las Ventas) on September 24, 1993.
Mano a Mano (Spanish for: Hand to Hand) is a compilation album released by the Mexican music ensembles Grupo Bryndis and Los Mismos.
Usage examples of "mano a mano".
Those party things are basically heavyweight challenges, mano a mano, if Irishka had refused to call a vote then she would have been finished anyway, so she had to call it no matter what, you should have seen the look on her face.