Cavani was left out of the Celeste squad by head coach Oscar Tabarez, paying the price for having not played since March.
"Nothing else," he noted. "In every practice, I asked them to fight, play strong defence and play smart in offense. This gave us the result in the second quarter."
Regarding Bayern's strategy, he said, the club's sports director Hasan Salihamidzic might have been surprised by the pandemic's effects.
United had a dream start when Bruno Fernandes scored a second minute penalty, but soon dropped behind as Tanguy Ndombele and then Son Heung-min netted for Spurs.
The defending champions, who had lost their first two games of the new season, have now bounced back with four consecutive wins to move up to second place.
Earlier on the Court Philippe-Chatrier, men's singles third seed, Dominic Thiem claimed another straight-set victory over 28th seed Casper Ruud, beating the Norwegian 6-4, 6-3, 6-1 to set up a last-16 clash against the winner between 2015 champion Stan Wawrinka and Hugo Gaston.
The event series includes the 2020 ITTF Women's World Cup, the 2020 ITTF Men's World Cup and the 2020 ITTF Finals.
Reims took an early lead through captain Yunis Abdelhamid's header in the 11th minute. But goals from Raphinha and Damien Da Silva put Rennes in front at the break.
Burel wasted three set points when she took a 5-3 lead in the first set and stormed to 40-0 in the ninth game. But Zhang battled back to save all three, and held the serve before breaking Burel's in the tenth to level the score at 5-5.
Colombia will face Venezuela in Barranquilla on Friday and Chile in Santiago four days later.
German media accused Bayern of having made panic acquisitions while under time pressure to find suitable deals.