World number seven David Nalbandian [ Images ] stayed on course for his first Stockholm Open title by crushing Spaniard Albert Montanes 6-4, 6-1 in the quarter-finals on Friday.

The top seed from Argentina broke serve once in the opening set and three times in the second to set up a meeting with third-seeded Finn Jarkko Nieminen, who ousted Spain's Oscar Hernandez 6-1, 6-4.

Nalbandian, making his debut in the tournament, has yet to drop a set this week.

Japanese teenager Kei Nishikori received a walkover when his Croatian opponent, second seed Mario Ancic, withdrew through illness.

"It's weird. I was thinking about pulling out myself as I haven't been feeling too well," Nishikori told reporters.

The 18-year-old, who has been troubled by a cold and a sore knee, is chasing his second tournament win having triumphed at Delray Beach in February by beating American James Blake [ Images ] in the final.

Nishikori next meets Swede Robin Soderling [ Images ], who put out fifth-seeded German Rainer Schuettler [ Images ] 6-2, 7-5.

Soderling, seeded four, broke in the final game to seal victory in one hour 13 minutes.

* 4-Robin Soederling (Sweden) beat 5-Rainer Schuettler (Germany [ Images ]) 6-2, 7-5; * Kei Nishikori (Japan [ Images ]) beat 2-Mario Ancic (Croatia [ Images ])(Ancic retired); 1-David Nalbandian (Argentina) beat 7-Albert Montanes (Spain)
6-4, 6-1; 3-Jarkko Nieminen (Finland) beat Oscar Hernandez (Spain) 6-1, 6-4.