Sir Henry Cecil's colt kept his unbeaten record intact under Tom Queally, recording his ninth successive Group 1 victory in the process despite a poor start which saw him stall in the blocks.
He was roared on by a crowd of 32,000 as Queally moved his mount to the front with one furlong remaining of the 1 mile and 2 furlongs trip.
And the bay, with the distinctive white marking between his eyes, surged away from last year's winner Cirrus Des Aigles to justify 2/11 favouritism and land his 14th consecutive victory and a first prize of £737,230.
"He's the best I've ever had, the best I've ever seen," said trainer Henry Cecil, who has praised Frankel for helping to sustain his battle against cancer.
Queally admitted that he had never been worried that there was any doubt over the win.
"He's getting more and more relaxed as time goes on. His class really showed today," said Queally.
"I walked the track and was worried about the conditions, but I walked the final straight and knew it wasn't too heavy."
The poor start meant that the victory margin of one and three quarters length was not his biggest, but the triumph never looked in question once he moved into position on the home straight.
Rated the world's best racehorse, four-year-old Frankel - owned by Prince Khalid bin Abdullah, part of Saudi Arabia's ruling family - will now go on to stud where he will earn millions each year siring future champions to add to the nearly £3 million he has already won in prize money.
Frankel's performance was the highlight of Champions Day, Britain's richest race day, featuring end of season races for top horses in five categories with Irish charges prevailing in the opening four.
Excelebration had suffered five defeats to Frankel, but won the Queen Elizabeth II Stakes over a mile. Aidan O'Brien's 10/11 favourite stormed clear of Cityscape with a furlong to run and won by three lengths.
Rite Of Passage took the opener, the Group 3 QIPCO British Champions Long Distance Cup, at odds of 8/1. Dermot Weld's former Ascot Gold Cup winner got up at the death to pip Aiken (4/1) by a neck.
Weld then doubled up as 5/2 joint-favourite Sapphire won the QIPCO British Champions Fillies' And Mares' Stakes. Shirocco Star (10/1) was two and a quarter lengths back in second under Kieren Fallon.
Maarek landed the QIPCO British Champions Sprint Stakes as the 5/1 shot hit the front with a furlong to go to win by three quarters of a length from the fast-finishing Hawkeyethenoo (25/1). Jamie Spencer was one of four jockeys who decided to stick to the stands and that was a decisive move as the David Nagle-trained runner landed the second Group 2 contest of the day.