Colombia goalkeeper David Ospina admitted on Thursday he was concerned Copa America referees may favour the United States on the eve of his team’s clash with the host nation in Santa Clara.

Arsenal star Ospina said he was wary of how match officials may react in Friday’s Group A opener at the Levi’s Stadium, where a near sell-out crowd will be overwhelmingly behind the Americans.

“We are worried about that,” Ospina said when asked about the referees. “But at the same time it’s a beautiful party. We wait for everyone to have good intentions. There will be a lot of respect in the soccer field, for the referees to do their job the right way.”

Colombia coach Jose Pekerman meanwhile played down the concerns, voicing optimism that “external” factors would not influence Friday’s game.

“Soccer is in a special moment,” the respected Argentinian said. “Everyone wants everything to be transparent. This is a great opportunity to show that technology and everything else is helping to improve the sport.

“We trust in the fairness and we hope there won’t be any problems, that nothing external that will influence the result of a game,” he added.