Correction: An earlier version of this article misidentified Sportimes player Jesse Witten.

The Washington Kastles improved to 8-2, emerging with a tension-packed 21-20 victory over the New York Sportimes at Kastles Stadium on the Wharf.

Frustration with officiating was the early theme, with Bobby Reynolds providing visuals of the distance by which he believed one shot was missed and Martina Hingis asking the chair umpire “are you sure?” after her serve was called out.

“You know that’s part of the game. It’s all in good fun,” Reynolds said. “We like to yell at [the chair umpire], we yell at other things — we just like to get the crowd going.”

All in good fun or not, fatigue from the grueling three-week World Team Tennis schedule contributed to the emotionally charged atmosphere. It also was plainly visible in the Kastles’ energy.

While Reynolds was able to gut out a tiebreak win in his singles match, Hingis looked a step slow in her 5-2 singles loss to Anna-Lena Groenfeld.

New York fell to 4-6.

Hingis, 32, also had to battle through her mixed doubles match with Raj Ram. She struggled with her first serve and floundered at the net — though she did successfully let out some frustration with one particularly emphatic slam that ended up two rows deep in the stands behind the baseline.

The duo broke serve to force a tiebreak, but there the inconsistency led to a 5-4 defeat.

Anger boiled over again in women’s doubles when Anastasia Rodionova whacked a plastic sponsor sign attached to the net. The sign shattered, and Rodionova was given a warning as the pieces were removed from the court.

She and Hingis channeled their anger a little more successfully after the incident, as Hingis dug deep to find some of the magic of her prime and give the Kastles a tiebreak set win.

The Kastles pulled out the win despite trailing, 18-16, heading into the final men’s doubles set.

There, Ram and Reynolds shone, though also not without controversy. New York’s Robert Kendrick was reprimanded for use of foul language as he and partner Jesse Witten failed to stop Ram and Reynolds from pulling the Kastles back even and ultimately taking the set 5-2, giving them the match by the slimmest of margins.