Spain's Carlos Alcaraz said on Monday the record prize money on offer at the Six Kings Slam in Saudi Arabia earlier this month was a motivation for playing in the tournament as the world No 2 prepares for the Paris Masters.
Italian rival Jannik Sinner dismissed earlier claims that he joined the exhibition event for financial rewards, emphasising that he went to Riyadh for the sporting challenge.
However, Alcaraz acknowledged the financial aspect played a role as he earned $1.5 million over four days in mid-October.
"I love playing tennis. You know, most of the time I don't think about the money. I just play for love or for fun. But you have to be realistic. You have to think that you want to earn money, you know, and that's it," Alcaraz told reporters on Monday.
"...in Arabia is the most highest prize money ever in the history, so that was a good motivation, at least for me."
The Spaniard has not experienced much success at the Paris Masters in recent years, with a quarterfinal appearance being his best result. Alcaraz captured the French Open and Wimbledon titles this year but said that the season has taken its toll.
"I haven't played good tennis here in this tournament. Probably at the end of the year, I have been tired, or yeah, as I said last year, I had to understand that the season is still going after September," he said.
"The calendar is super tight, super demanding, as well. So coming to the last tournament of the year, probably I have been tired the last year, didn't play as well as I wanted, but coming to this year, I think I'm feeling different."
The top seeds begin their campaigns on Tuesday while some matches started earlier on Monday.
Greek 10th seed Stefanos Tsitsipas rallied to beat Spain's Roberto Carballes Baena 4-6 6-3 6-3 in the round of 64, while France's Adrian Mannarino shocked American 11th seed Tommy Paul 6-3 7-5.
Alcaraz will play Chilean Nicolas Jarry in the round of 32 on Tuesday.
The Paris indoor tournament runs until November 3.