Answer
Andre Agassi, a former world No. 1 tennis player and eight-time Grand Slam champion, was appointed as part of Grigor Dimitrov's coaching staff in May 2019, with Štěpánek joining him as co-coach. The collaboration, which marked a significant development in Dimitrov's coaching team, aimed to enhance the player's performance and strategic approach on the court, drawing on Agassi's vast experience and success in the sport.