World number one Rafael Nadal chalked up his 11th victory in a row on Saturday, defeating unwell Frenchman Gael Monfils 6-4, 6-4 to reach the final of the World Indoor Tournament.
The Spaniard next plays Britain's Andy Murray, who destroyed Croatian Mario Ancic 6-1, 6-2.
Monfils, the only player to beat Nadal this year in the Qatar Open quarter-finals last month, made a poor start by dropping his first service game.
He broke back but then surrendered his serve again in the fifth game.
Nadal, who went to three sets in his previous three matches this week, only needed a single break in the second set to close out Monfils.
"I feel sorry for Gael," Nadal told reporters. "He did not play his best because of stomach problems and I was thinking more about him than myself.
"I saw him vomit when I went to the toilet after the first set. That disturbed my concentration and afterwards I made more mistakes."
Nadal said he would need to be back to his best against Murray on Sunday.
The second-seeded Scot raced through the first set against Ancic in 24 minutes and maintained his rhythm to clinch his second final appearance of the year, after winning in Doha last month.
Murray, though, said an ankle injury would prevent him playing in Marseille next week.
"It felt uncomfortable after yesterday's quarter-final," he said. "I hope it will not be a problem for the final.
"It didn't bother me today as I played really well.
"The physio examined my ankle but could not find any damage. Next week I will try getting my ankle better and prepare for the hardcourt tournaments to come."