Federer is just one win away from securing his seventh ATP Tour title of the year - after winning prestigious events such as the Australian Open, Miami Masters, Indian Wells Masters and Wimbledon, to name a few.
Del Potro served out the match to move into a semi-final against second-seeded defending champion Marin Cilic, who struggled for three hours to beat 100th-ranked Hungarian qualifier Marton Fucsovics 7-6 (7/3), 5-7, 7-6 (7/4).
"What can I say after this match?" I enjoy playing in Basel.
"I played a smart match, I waited for my chances in both sets", Del Potro told reporters after his 6-4 6-4 win over the world number four.
And Del Potro, 29, revealed his amazement that the 19-time Grand Slam champion is still going strong. He swiftly levelled the match and after fending off break points early in the decider broke himself and completed a 4-6 6-1 6-3 victory.
Federer may have been the dominant force in his home tournament since a maiden triumph in 2006, but back-to-back final defeats to Del Potro in 2012 and 2013 will have rankled.
"I'm doing well, but in the final, anything can happen".
"I'm having a good end of year, it's giving me motivation looking forward to next year".
Federer has been powering through the week as he tries to overhaul rival Rafael Nadal to finish the year as world number one. "Roger is the favourite to win - but I will see what I can do".
The battle is provisionally scheduled to continue next week at the Paris Masters, but the 36-year-old Swiss will make a late decision on whether or not to take up his second-seeded position at Paris Bercy after the Basel final.
- Sunscreen Snow Falling On Exoplanet Detected By Hubble Space Telescope
- Caitlyn Jenner Fulfills 'Fantasy' Of Walking On The Beach In 'Authentic Self'
- Rahul Gandhi's dog tweet irks Assam minister
- Texas A&M's home losing streak to SEC West opponents is incredible
- Almost entire Texans team protests after owner firestorm
- Selena Gomez talks about kidney transplant
- Most Texans players join 11 Seahawks in protest
- Four shot in Central Austin by man dressed as Santa Claus
- Caroline Wozniacki stands firm to claim WTA Finals title
- Patriots Hold Off Chargers 21-13 for 4th Straight Win