Petr's father, ex-world number two who won the Australian Open in 1998, will be busy following his children Sebastian, 20, Jessica, 28, and Nelly, 22, on Thursday.
Then Sebastian will play the quarterfinals in Miami against the Russian Andrej Rublev.
Now Sebastian hopes that the parents (mother is Regina who was named Rajchrtová as unmarried and was 26th in the ranking as the best) will stay and watch the quarterfinals in Miami.
- It's incredibly cool that both my parents are here.
They would fly to Palm Springs today to see my sisters play golf but hopefully they will stay here instead, Sebastian says to the ATP Tour after the biggest victory of his life, the first against a top 10 player.
"Like father Like Son"
The 87-ranked Korda was the only one of four American players who managed to win in tonight's round of 16.
Petr has sometimes been a caddy for the daughters who debuted at the US Open at the ages of 14 and 15 respectively.
Nelly is world four while Jessica is 18th in the ranking.
"Like father Like Son.
28 years after dad Petr, 'Sebi' goes to the quarterfinals of the Miami Open.
I love it ", Jessica and Nelly tweet in identical tweets where they have made a video collage with both players who are confusingly similar to each other.
See the clip here (external link).