Watch: Serena Williams drops by Washington for surprise practice session

Serena Williams surprised fans and others present on and around the grounds of the Citi Open in Washington DC as she arrived for a practice session there early on Sunday. The 23-time Grand Slam champion is not part of the 2022 Citi Open draw but is preparing for her comeback at the National Bank Open in Toronto next week, which will kickstart her North American summer hardcourt swing.

In a video posted on social media by the Citi Open page, Williams can be seen making her way towards the practice court. She was surrounded by many excited fans, whom she greeted with a smile.

"The best Sunday surprise. 23-time Grand Slam champion Serena Williams stopping by for a DC morning practice," read the caption of the post on Twitter.

The American superstar was then seen smashing a few backhands during the practice session.

Her older sister Venus Williams is set to make her singles comeback in the opening round of the Citi Open on Monday, almost a year since her last singles match on the WTA tour. She will open her campaign against a qualifier in the third round.

Meanwhile, Serena Williams is scheduled to play both WTA 1000 events ahead of the 2022 US Open. Williams will play at the National Bank Open in Toronto, which begins on August 8, before participating in the Cincinnati Open the following week. After a week's rest, she will make a comeback at her home Grand Slam tournament - the US Open, where she last played in 2020 and reached the semifinals.

Next week's National Bank Open will be just her second tournament this year. She recently played at the 2022 Wimbledon Championships, which was her first tournament since Wimbledon 2021. She lost in the opening round to Harmony Tan in three sets.

Looking back at Serena Williams' last US Open campaign in 2020

2020 US Open - Day 10

Serena Williams entered the 2020 US Open on the back of a second-round loss at the Cincinnati Open. She started her US Open campaign with two straight-sets wins against Kristie Ahn and Margarita Gasparyan. She then faced 2017 champion Sloane Stephens in the third round and lost the opening set 2-6, before storming back to win the match 2-6, 6-2, 6-2. Williams then had another three-set battle, but overcame Maria Sakkari to reach her 17th US Open quarterfinal.

Williams then produced another memorable comeback in the tournament, this time against Tsvetana Pironkova in the quarterfinals, and eventually won 4-6, 6-3, 6-2 to reach her 14th semifinal at the New York Major. In the semifinal against Victoria Azarenka, Williams rushed to a 6-1 lead, but could not keep up her momentum and bowed out of the tournament with a 1-6, 6-3, 6-3 loss to Azarenka.

Serena Williams is still gunning for a record-equalling 24th Grand Slam title. Her last Grand Slam title was at the 2017 Australian Open. The 40-year-old has lost four Grand Slam finals since then, two of them at the US Open.