WTA Finals open with delay; defending doubles champions win

WATCH: Tennis Channel Live previews Day 1 of the WTA Finals as play begins on Monday in Fort Worth.

FORT WORTH, Texas (AP) — The WTA Finals began with a bit of a hiccup—an odd delay of several minutes caused by a questioned line call on the third point—and a victory Monday for defending doubles champions Barbora Krejcikova and Katerina Siniakova.

The Czech duo, who won three major championships together this season and completed a career Grand Slam, beat Desirae Krawczyk of the U.S. and Demi Schuurs of Netherlands 6-4, 6-3 on the temporary indoor hard court at Dickies Arena to open the season-ending tournament.

The other matches scheduled for later on Day 1 were Jessica Pegula vs. Maria Sakkari, Ons Jabeur vs. Aryna Sabalenka, and Pegula and Coco Gauff in doubles against Xu Yifan and Yang Zhaoxuan.

There were a few hundred spectators scattered around the stands at the outset, leaving thousands of empty gray seats, and the courtside radar readouts initially displayed serve speeds in kilometers per hour instead of the more U.S.-friendly miles per hour, which was quickly changed.

With Krawczyk serving to Krejcikova at 30-love in the very first game, the electronic line-calling system ruled a 100 mph offering an ace. Krejcikova held a finger and thumb apart to show that she thought the ball landed out and asked to see a replay. No such video ever appeared.

That prompted a lengthy break as players and the chair umpire discussed how to handle the situation. Eventually, the point was replayed—and again won by Krawczyk, this time with a passing shot.