Argentinian side Tigre edged out Paraguayan giants Olimpia 2-1 to boost their hopes of reaching the quarter-finals of the Copa Libertadores.
In the first leg of their round-of-16 tie, Tigre once again showed the sort of form that carried them to the Copa Sudamericana Finals in December.
In the northern suburbs of Buenos Aires, it was midfielder Gabriel Penalba who put Tigre ahead with a left-footed strike in the 25th minute.
They doubled their lead through Matias Perez-Garcia's header 18 minutes into the second half, but Olimpia got what might be a crucial goal back thanks to Herminio Miranda's free-kick in the 77th minute.
That leaves the tie delicately balanced ahead of the second leg on August 16th.
"We knew it was a must-win match and we won it," Tigre midfielder Perez Garcia told Fox Sports.
"Their goal hurt us a little bit, but in Paraguay we will be playing out another battle.
"This team wants to make history and we took an important step tonight."
Reigning Brazilian champions Fluminense or Ecuador's Emelec will await the winners of this tie in the next round.
Olimpia forward Juan-Manuel Salgueiro is still confident it could be his side in that semi-final.
"The tie is still open," he said. "Miranda's goal was very important so we'll progress by winning 1-0."
Reigning Mexican champions Tijuana played out a goalless draw with Brazilian side Palmeiras at home, an encouraging sign for the visitors who had lost all of their previous away games in this season's tourament.
"It was a good game for us," said Palmeiras midfielder Marcio Araujo. "We created opportunities to score, but failed to finish them. At home, we have what it takes to beat them.
"We expected to face a good team in dead ball situations, but we managed to deal with that. We played well tactically and took a good point back home."
The winners of this tie will play either Atletico Mineiro or Sao Paulo in the next round.