The Astana Open is an ATP 500 event played indoors at the National Tennis Center, but two of its top stars were hitting outdoors on Sunday.

For one day only, though.

Daniil Medvedev and Felix Auger-Aliassime, the second and eighth seeds, respectively, exchanged leisurely strokes as part of a pre-tournament activity at the city’s famous Baiterek observation tower.

Looking on was the president of the Kazakhstan Tennis Federation, Bulat Utemuratov, and he would have been pleased with the feedback from both players.

“They set up a full-size tennis court in the heart of the city so it’s a great effort from them to make everything nice,” said Auger-Aliassime, who posted victories over new World No. 1 Carlos Alcaraz and Novak Djokovic in back-to-back weeks in September. “And I think it shows how much they have [had] attention to detail.

“From the first moment we got here as players, they’ve been really meticulous with every detail of the tournament. I’m glad we’re here and I’m glad we had the chance to play on this court.”

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Medvedev, last year’s US Open champion, recalled that he played an ATP Challenger Tour event in Astana six years ago. Back then he was ranked No. 174 and made the quarter-finals, defeated by Denis Istomin.

“I have to say I love Kazakhstan,” said Medvedev. “It’s really close to my culture. I can speak my language here. I’m always happy to come back here, and as Felix said, the tournament is doing a really great job.”

Auger-Aliassime, who did not compete in Astana when it hosted an ATP 250 the previous two seasons, was also impressed with the capital.

“Not too far from Europe but also Asia, so I think we have a bit of mix of cultures, and it’s a beautiful city,” the Canadian said.

Visitors to Astana often flock to the Baiterek, which Lonely Planet partially describes as “a white latticed tower crowned by a large glass orb. This embodies a Kazakh legend in which the mythical bird Samruk lays a golden egg containing the secrets of human desires and happiness in a tall poplar tree, beyond human reach.”

It stretches 97 metres above the ground.

Who will be flying highest on the court this week remains to be seen.

Medvedev begins against Spain’s Albert Ramos-Vinolas and Auger-Aliassime meets another Spaniard, Roberto Bautista Agut. Alcaraz and Djokovic are part of the impressive field, too.

Medvedev and Auger-Aliassime have battled in the past in the latter stages of the Australian Open and US Open, Medvedev winning on both occasions.

They could duel again in the quarterfinals this week, with the stakes higher than on Sunday at the Baiterek.