World men's tennis number one Rafael Nadal will miss Spain's Davis Cup final against Argentina this month after failing to recover from tendinitis in his knee.
Nadal says it's been an extremely difficult decision and he has done everything possible to get fit.
He says he's used to playing with pain but this is a new and different pain he can't control.
The injury forced Nadal to pull out of this week's season-ending Masters Cup in Shanghai and he also had to retire from his Paris Masters quarter-final against Nikolay Davydenko last month.
The Spanish tennis federation is expected to name its team tomorrow for the tie in Mar del Plata starting on November 21st.
The French Open and Wimbledon champion has previously blamed his injury on an overloaded tennis calendar.