The Serena Williams ticket demand keeps going up (and up and up).

The further Serena Williams advances into the U.S. Open, the more tickets cost to see her.

For Williams’s doubles match with her sister Venus on Thursday in Arthur Ashe Stadium, the cheapest seats available for resale on Ticketmaster were well over $340 each in the nosebleeds.

Those who want a better view of the Williams sisters will need to pay substantially more. Resale tickets for Thursday in the midlevel of Arthur Ashe were selling for about $1,000 and up as of Thursday, and tickets in the lowest level of the stadium were selling for more than $7,500 each.

For Williams’s third round singles match against Ajla Tomljanovic of Australia on Friday night, tickets were north of $500 for the cheapest seats. Tickets in the midlevel of Ashe were selling for about $3,000, and more than $9,000 in the lowest level of the stadium.

Williams is having an obvious effect on ticket prices, according to Logitix, a ticketing technology company. Before she won her second-round match against Anett Kontaveit on Wednesday, the cheapest tickets for a Friday night match in Arthur Ashe were $160, then jumped to $450 after Williams won, according to Logitix. Tickets in the midlevel of Ashe before she won were selling for $405, then shot up to $1,530. Courtside tickets were going for $805 before the win and $3,500 after the win.

While the final is still more than a week away, with several rounds in between, tickets for the women’s final are also up. Those who looked for tickets to the Sept. 10 final before Williams announced she planned to retire could have found some tickets for about $150. Since Williams has advanced to the third round, the cheapest tickets for the women’s final have now doubled, to about $300 on Ticketmaster.