Basle, Switzerland - Roger Federer and David Nalbandian take their rivalry into an 18th career meeting after the pair rolled to straight-set semi-final victories on Saturday at the Swiss Indoors.

Top seed Federer, aiming to lift his third consecutive home trophy at the St Jakobshalle, overcame an early wobble to put out unseeded Spaniard Felicano Lopez 6-3, 6-2 in 61 minutes.

Nalbandian continued his charmed life at the event, blasting to his fourth final in seven appearances with a defeat of Argentine countryman Juan Del Potro 6-4, 6-4.

Del Potro is dealing with a painful split toenail which he has not time to have removed until the end of a breakthrough season which could include the Masters Cup and will definitely feature an historic Davis Cup final at home against Spain.

Nalbandian now stands 2-1 over his 20-year-old teammate after losing to Del Potro in the Madrid third round a week ago.

Federer solved his teething problems against Lopez, a player he had beat in all six of their previous meetings, by saving two break points in the third game, which he concluded with an ace.

That settled, the 13-time grand Slam champion raced away with the first and on started the second in the best possible way with a break for 1-0 after Lopez double-faulted into a break point.

Federer secured a second break and concluded with his a match point lined up with ace number 15.

He and Nalbandian have a tight series, the Swiss leading 9-8 with a win this year in Monte Carlo.

"We know each other's games so well, we've been playing since we were juniors," said Federer, "It's always tough to play David.

"I had a slow start today but I managed to correct things and play my tennis."

Federer won his 62nd match of the season against 13 defeats.

Nalbandian said it is usually luck of the draw when he plays Del Potro. "Today I was lucky and last week it was him. It was an even match. It all depends on who wakes up feeling better."

Nalbandian has prospered frequently in Basle, winning the tournament out of the box in 2002 on his first appearance. He came back to play finals at the next two editions but lost in the first round last year.

Both Argentines remain in contention for one of the remaining places in next month's Masters Cup season wrapup in Shanghai.

But with Davis Cup looming. Nalbandia has said that even if he makes the field, he will not travel to China.

Del Potro is keen to play both big events if possible and has no problems with flying the Pacific from China to Argentina after Shanghai.

"Rafa (Nadal) and David Ferrer (from Spain) will be doing the same so we will all be in the same condition," said Del Potro, who admitted: "Right now I'm tired physically and mentally."

Del Potro won four straight titles over the summer, and has claimed 35 or 39 matches since July on three different surfaces. (dpa)