Rafael Nadal remains on course to win a 12th Monte Carlo Masters title after coming through a tough two-set encounter with Guido Pella 7-6 (7-1) 6-3 on Friday.

The Spaniard was pushed hard by the in-form Pella before eventually securing an 18th straight triumph in the tournament after two hours and 20 minutes on court.

After Novak Djokovic's shock exit in the previous match, an expectant crowd witnessed Nadal fall into an early hole in the opening set.

Pella recorded two breaks of serve to ease into a 4-1 lead and while his opponent hit back, taking the next four games on the spin, the Argentinian had the chance to serve out for the set when he caught Nadal out to go 6-5 in front.

However, the second seed responded to the concerning situation in impressive fashion.

After drawing level to force a tie-break, Nadal proceeded to seize control by winning the first six points, eventually sealing a see-saw set after 82 minutes.

Nadal then jumped out into a commanding lead in the next set, a pair of breaks putting him 4-1 up in a hurry.

He was forced to wait to clinch victory, though, failing to serve out for the match when 5-2 ahead. Still, it was only a minor setback as a break in the next game finally sealed a hard-fought triumph for the 'king of clay'.

Nadal - who has now won an astonishing 25 sets in a row in Monte Carlo, a run stretching back to his opening encounter against Kyle Edmund in 2017 - will face either Borna Coric or Fabio Fognini for a place in the final.