Rafael Nadal expects the "toughest quarter-final of my career" against Novak Djokovic at the French Open.
Nine-time champion Nadal beat Jack Sock 6-3 6-1 5-7 6-2 in round four to claim a record 70th win at Roland Garros.
The Spaniard is trying to become the first player in the Open era to win 10 titles at any Grand Slam event.
Nadal has defeated Djokovic - who beat Frenchman Richard Gasquet 6-1 6-2 6-3 - six times in the French Open, including in each of the last three years.
However, the Spaniard has only won one tournament since Paris last year, while top seed Djokovic is on a 26-match winning streak.