Walid El Karti nodded a deep cross past goalkeeper Ronwen Williams at the far post in the 94th minute to stun a sell-out 50,000 crowd at Loftus Versfeld stadium in Pretoria.

Sundowns had taken the lead after 54 minutes through Brazilian Lucas Ribeiro, who ended a 1,080-minute Champions League goal drought by scoring from close range at the second attempt.

His first shot was parried by goalkeeper Ahmed el Shenawy, but he made no mistake when he regained possession, slamming the ball into the roof of the net.

The teams clash again on June 1 in Cairo with Sundowns seeking to win the premier African club competition a second time and Pyramids for the first time.

Sundowns were also held at home by Pyramids in the group stage of the last Champions League and won the return match in Cairo through a Teboho Mokoena goal.

"I was unhappy with our performance in the last 10 minutes -- we dropped too far back," said Sundowns' Portuguese coach Miguel Cardoso.

"Conceding so late obviously is disappointing, but we can score in Cairo and win the return match there.

"The Pyramids midfielders were very aggressive and that is something we have to counter in the second leg.

"I am not making excuses, but the pitch was very slippery and that did not suit our style," added the coach who lost the last Champions League final with Esperance of Tunisia.

Pyramids coach and former Croatia midfielder Krunoslav Jurcic pleaded with Egyptian football followers to attend the return match next Sunday.

When the Cairo outfit won at home to another South African club, Orlando Pirates, in the semi-finals, only a few thousand cheered them on in a 30,000-seat stadium.

"Please come to the stadium and support us. We are playing for all of Egypt. Your backing can be a crucial factor," said Jurcic.

"We had energy today, we had knowledge of Sundowns, but this final is far from over. Sundowns beat us in Cairo in the last Champions League."

Pyramids are playing in the Champions League for only a second time while Sundowns have made 17 previous appearance, including beating Zamalek of Egypt in the 2016 title decider.

After the second leg, Sundowns will switch their focus to the Club World Cup in the United States, where they face Fluminense, Borussia Dortmund and South Korean side Ulsan in Group F.