Editor's note: This feature was first published on Feb. 10. On Wednesday, Pegula defeated No. 10 seed Daria Kasatkina 6-3, 7-5, coming from 5-3 down in the second set, to reach the Doha quarterfinals.

World No. 5 Jessica Pegula knows that well. The 30-year-old American came into her own in the last five seasons to emerge as an immovable bedrock in the Top 10. While fast hard courts remain her bread ...