Nadal is bidding to win this tournament for the sixth time but believes the rapidly improving Dimitrov, who beat Roberto Bautista-Agut in three sets to book his place in the last four, will represent a hard opponent.
He also finished runner-up to Novak Djokovic in the 2013 and 2015 finals. Nadal now leads Dimitrov 8-1 in their ATP Head-to-Head series.
Federer returns to action at next week's Shanghai Rolex Masters, where 1,000 points are awarded to the victor.
The top-ranked Spaniard, who won the French Open and US Open this year, saved all six break points he faced and increased his lead over Roger Federer at the top of the rankings.
The left-hander, in turn, broke Khachanov three times to prevail in 89 minutes.
He will now face big-hitting American Isner, who thrashed Leonardo Mayer 6-0 6-3 to book his place in the last-eight of the tournament.
Nick Kyrgios cut a disgruntled figure during the final
They were the only break points he managed in the set, but Nadal earned just one and failed to capitalise as the pair remained all square. He would look to use his solid groundstrokes and powerful serves and overpower the defensive-minded Nadal, who could be aggressive at times.
He said: "Happy about the match today".
Also, third-seeded Grigor Dimitrov eliminated Juan Martin del Potro 7-6 (6), 7-5, Steve Darcis defeated Dusan Lajovic 6-3, 6-4 and fifth-seeded Roberto Bautista Agut beat Aljaz Bedene after the British player retired from the match in the second set. "But if you add that he is playing very well now from the baseline, he is one of the toughest opponents you can meet". He's playing unbelievably well.
"We go on court and we try our best and we want to win".
"So let's see what's going on tomorrow".
The 32-year-old Isner is eyeing his third ATP World Tour crown of the season this week after victories in Newport and Atlanta.
Hawkeyes react to last-second fall to Penn State
Catch it, will ya: Brandon Polk dropped a completion that would have sustained a Penn State possession in the second quarter. By comparison, Penn State had 13 turnovers gained - 10 picks, three fumble recoveries - in 14 games last season.
The vote was strongly opposed by the central government in Baghdad, Iran, Turkey and other countries including the United States. They have agreed to increase economic cooperation as well as joining forces to address major issues in the Islamic world.
The main opposition Democratic Party has been suffering in the polls, with only eight percent of voters planning to vote for them. Mr Abe said: "I expect opposition criticism is going to focus on (the scandals), and it's going to be a very hard election".
With rumors swirling about Westbrook potentially being swayed to leave in free agency next summer, people were rightfully nervous. Westbrook , the league's reigning MVP, has been sitting on the deal for months; the Thunder first dangled the deal in July.
Israel lobbies hard against Palestinian efforts to join global organisations to advance their goal of statehood. General Assembly meeting in Beijing, a day after Palestinians praised a terrorist who killed three Israelis.
And a deal has also been reached for Russian Federation to supply Saudi with S-400 anti-aircraft missiles. Vision 2030, a blueprint for Saudi Arabia to move its economy away from oil, is driving that change.
The IEA put much of the solar surge down to a large reduction in the cost of deployment and increased support from governments. The IEA report comes as Ottawa aims to drastically cut carbon emissions, largely by expanding renewable energy capacity.
Spain's central government says the referendum goes against the country's 1978 constitution, which states Spain is indivisible. Twelve Catalan government officials arrested last week have been released, but six remain under investigation.
Cuban officials say they're disappointed in the U.S. retaliatory measures but will continue cooperating with the investigation. Share with Us - We'd love to hear eyewitness accounts, the history behind an article, and smart, constructive criticism.
The transport body also queried Uber's use of Greyball software , which could be used to block regulators' access to the app. Earlier this year, Transport for London renewed its license on a limited basis, giving it six months to address concerns.
Her policy platform includes free tertiary education and slashing immigration to reduce pressure on housing and infrastructure. Both parties are now courting the populist New Zealand First party, which won nine seats, to form a coalition.
WHAT'S HAPPENING: Girlfriend denies knowledge of Vegas plot
As for what motivated the actions of his brother, Eric Paddock said he and his family are "still just completely befuddled". Investigators reached Marilou Danley early Monday but do not believe she was involved in the shooting at this time.
Tropical Storm Nate forms over Nicaragua
A north-northwestward motion at a faster forward speed is forecast to begin on Thursday and continue through late Friday . The storm's eye is expected to move near the coast of Mexico's Yucatan peninsula late Friday into Saturday morning.
Samsung does Windows Mixed Reality with Odyssey HMD headset
The Samsung HMD Odyssey looks like it might surpass existing Windows MR devices from Acer , Asus, Dell , HP and Lenovo . The headset offers a 110-degree field of view, and its spatial AKG headphones are created to put sound all around you.
Canada Terrorism Suspect Was Investigated for Extremism
Just before midnight the same evening, a U-Haul truck was pulled over at a checkstop location on Wayne Gretzky Drive and 112 Ave. Based on the actions and the evidence at the scene, the incidents were being investigated as "acts of terrorism ", police said .
Kent's Henry Bolton becomes latest Ukip leader
UKIP should not become a one-issue party centred around Islam, the party's leader in the Welsh Assembly Neil Hamilton has said. A banner was superimposed with an image of Mr Farage posing as Adolf Hitler with the European Union logo in the background.
Ex-Porsche executive arrested in Audi emissions probe
Volkswagen said on September 29 it was increasing provisions related to its Dieselgate scandal by 2.5 billion euros. VW first admitted in September 2015 that it had used illegal software to cheat USA emissions tests.
Coroner's report deepens mystery of Otto Warmbier's death
Sammarco said she agreed with UC Health system doctors who treated Warmbier and said they found no evidence of botulism. US President Donald Trump tweeted: "Great interview on @ foxandfriends with the parents of Otto Warmbier: 1994 - 2017".