Rafael Nadal blitzed Federico Delbonis 6-1 6-1 to reach the final four of the Argentina Open on Friday, while Juan Monaco upset third seed Pablo Cuevas.
In a relatively one-sided day of action, Monaco versus Cuevas was the only quarter-final to go to three sets, as Nadal, Carlos Berlocq and Nicolas Almagro cruised into the semi-finals.
Nadal broke Delbonis five times as he wrapped up victory in just 63 minutes, with the first seed reaching the last four for the second straight tournament, after being eliminated by eventual runner-up Fabio Fognini in the semi-finals of the Rio Open last week.
Another local awaits Nadal in Argentina's capital, with Berlocq representing the world number four's next hurdle.
Berlocq defeated Blaz Rola 6-1 6-3 in one hour, 20 minutes.
In the tightest match of the day at the ATP 250 event, Monaco needed over two-and-a-half hours to see off Cuevas 7-6 (7-1) 6-7 (4-7) 6-4.
Monaco started well, breaking Cuevas in the opening game, but with both players struggling to hold serve - the first set included six breaks - a topsy-turvy contest started to emerge between the two Argentinians.
Cuevas levelled at 2-2, Monaco surged into a 4-2 lead and the third seed reeled him in again.
Monaco had to serve to save the set at 6-5 down and then won the first three points of the tie-break as he dominated Cuevas 7-1.
Cuevas looked done for at 5-2 down in the second set but won three straight games to level, dropped behind at 6-5 and then held serve for another tie-break, which he shaded 7-4.
But in the third set, there was just one break of serve - in the ninth game in favour of Monaco - as the 30-year-old secured victory.
"It was a relief, because it was a difficult and long match," Monaco told the ATP's website.
"I celebrated the way I did because I enjoy it. Having such feelings is what I missed most about tennis.
"I am very motivated because I have the opportunity to play a final again and here in Buenos Aires. That excites me a lot, and I hope to play the best way to win tomorrow."
Monaco will take on Almagro in the last-four after the Spaniard triumphed 6-3 6-2 over second seed Tommy Robredo.