Question: Casey Dellacqua and Yevgeny Kafelnikov are both what?

Context paragraphs:
Yevgeny Kafelnikov: Yevgeny Aleksandrovich Kafelnikov (Russian: Евгений Александрович Кафельников ] ; born 18 February 1974) is a Russian former world No. 1 tennis player.  He won two Grand Slam singles titles, the 1996 French Open and the 1999 Australian Open.  He also won four Grand Slam doubles titles, being the last man to have won both the men's singles and doubles titles at the same Grand Slam tournament, which he did at the 1996 French Open.

Casey Dellacqua career statistics: This is a list of the main career statistics of professional Australian tennis player, Casey Dellacqua.  To date, Dellacqua has won eight career doubles titles: one grand slam mixed doubles title with Scott Lipsky at the 2011 French Open and seven WTA doubles titles including one Premier Mandatory doubles title with Yaroslava Shvedova at the 2015 Mutua Madrid Open.  Other highlights of Dellacqua's career include reaching the doubles finals of all four grand slams; a quarterfinal finish in singles at the 2014 BNP Paribas Open and fourth round appearances at the 2008 Australian Open and 2014 Australian Open and US Open respectively.  Dellacqua achieved a career high singles ranking of World No. 26 on September 29, 2014 and later achieved a career high doubles ranking of World No. 3 on February 1, 2016.

2013 Aegon Trophy – Women's Doubles: Eleni Daniilidou and Casey Dellacqua are the defending champions, having won the event in 2012.  Dellacqua chose not to defend her title; Daniilidou partnered up with Coco Vandeweghe, but they lost in the quarterfinals.

2000 Torneo Godó – Doubles: Paul Haarhuis and Yevgeny Kafelnikov were the defending champions, but Kafelnikov chose to not compete this year in order to focus on the singles tournament.

1996 Estoril Open – Doubles: Yevgeny Kafelnikov and Andrei Olhovskiy were the defending champions but only Kafelnikov competed that year with Paul Haarhuis.

1999 Australian Open – Men's Singles: Petr Korda was the defending champion, but he was eliminated in the third round by Todd Martin. <br>Yevgeny Kafelnikov won the title, defeating Thomas Enqvist in the final, 4–6, 6–0, 6–3, 7–6.  With this win, Kafelnikov became the first Russian (male or female) to win the Australian Open.

1996 Grand Prix de Tennis de Lyon – Doubles: Jakob Hlasek and Yevgeny Kafelnikov were the defending champions but they competed with different partners that year, Hlasek with Guy Forget and Kafelnikov with Daniel Vacek.

2001 CA-TennisTrophy – Doubles: Yevgeny Kafelnikov and Nenad Zimonjić were the defending champions but only Kafelnikov competed that year with Wayne Ferreira.

2004 Legg Mason Tennis Classic – Doubles: Yevgeny Kafelnikov and Sargis Sargsian were the defending champions, but did not compete this year, with Kafelnikov retired at the end of the 2003 season.

Casey Dellacqua: Casey Dellacqua (born 11 February 1985) is an Australian professional tennis player of Italian and Irish descent.  Dellacqua's best singles results to date have been semifinal appearances at the 2012 Texas Tennis Open and 2014 Aegon Classic, a quarterfinal finish at the 2014 BNP Paribas Open and fourth round appearances at the 2008 Australian Open, 2014 Australian Open and the 2014 US Open.

Supporting paragraphs: Casey Dellacqua Yevgeny Kafelnikov
Answer: tennis player