Possible Clues:

• Tennis champ nicknamed “The Punisher”
• Tennis great who wrote the 2009 tell-all 'Open'
• First man to achieve a Career Golden Slam
• Tennis star with marriages to Brooke Shields and Steffi Graf
• His 2009 autobiography was titled 'Open'
• Eight-time tennis Grand Slam champion
• "Open" autobiographer
• Graf's doubles partner?
• Sampras opponent in five Grand Slam finals
• Tennis champion with the 2009 memoir 'Open'