NEW YORK – Robson Conceicao’s first fight since his loss to Shakur Stevenson ended strangely Saturday night.

Nicolas Polanco couldn’t continue beyond the second round after an accidental clash of heads apparently left him disoriented. Their junior lightweight fight, which was scheduled for 10 rounds, ended in a no-contest because the Dominican Republic’s Polanco couldn’t answer the bell for the third round on the Josh Taylor-Teofimo Lopez undercard in The Theater at Madison Square Garden.

Conceicao’s head hit Polanco on the chin as Conceicao raised it during an awkward entanglement late in the second round.

Polanco went down and had difficulty reaching his feet. Referee Eddie Claudio eventually helped Polanco get up.

Some fans booed because they thought Polanco was exaggerating the extent of his injury.

Polanco sat on his stool once Claudio called for a break, but he left his corner and was willing to continue late in the second round. The bell rang to end it before either fight could throw a punch, however, and Polanco went back to his corner.

Once Polanco sat down following the second round, a ringside physician for the New York State Athletic Commission determined he couldn’t continue.

Brazil’s Conceicao (17-2, 8 KOs, 1 NC) had hoped to win impressively in the 2016 Olympic gold medalist’s first fight since Stevenson beat him decisively in their 12-round, 130-pound title fight last September 23 at Prudential Center in Stevenson’s hometown of Newark, New Jersey. Polanco (20-4-1, 11 KOs, 1 NC) lost three straight bouts before he faced Conceicao.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.