Dominic Gardiner-Hill believes Frankel is capable of taking his rating to even more astonishing levels after the British Horseracing Authority's handicapper allotted the colt a mark of 138 for his victory in Saturday's JLT Lockinge Stakes at Newbury.
The decision to raise him 2lb from last season's 136 makes Frankel officially the highest-rated horse in the world for 25 years.
Khalid Abdullah's colt can only be trumped by the same owner's Dancing Brave (141 in 1986), although the World Thoroughbred Rankings scale has been lowered slightly since that time.
Frankel leaves behind Peintre Celebre and Generous on 137 and Sea The Stars on 136.
Gardiner-Hill was no different to the entire racing community in being impressed by Frankel's fourth and most clear-cut defeat of Excelebration as the son of Galileo brushed off any fears over a slightly interrupted preparation.
"I do think he can go higher," said the handicapper. "I watched the Lockinge again today and, to be honest, he did it very easily."
Gardiner-Hill added: "To go higher he is going to have to beat something other than Excelebration, whether it is going to be a horse like Cirrus Des Aigles, we will have to wait and see.
"I do suspect he can be a 140-horse, it just depends if he gets the opportunity."
Reflecting on his thinking over the mark of 138, which must first be ratified by his international colleagues, Gardiner-Hill said: "I'm happy with the rating. My first reaction to the Lockinge was one of relief, as Frankel had confirmed what he had shown last season."
"It's always a concern when you give ratings in the mid 130s that it might not work out for the horses as four-year-olds but I think there are valid reasons for saying this was his best performance yet," continued Gardiner-Hill.
"You only have the opportunity to push horses higher on what they beat, and if you look at Excelebration, Frankel beat him by four lengths on two occasions last year and by two and a quarter on another, and this went up to five lengths on Saturday.
"And in the case of Dubawi Gold, he was beaten by seven and three-quarter lengths in the QEII and this went up to nine on Saturday.
"One factor for this is the pace as I thought Ian Mongan set the race up perfectly on Bullet Train.
"I'm not blaming Ian Mongan's riding at all on other occasions, but this was the first time that everything went spot-on for Frankel in terms of pace."
Frankel will now be rated 6lb higher than the second-placed horse in the current international rankings, Australian sprinter Black Caviar (132), who is due to arrive in the UK next month for her first overseas test at Royal Ascot.
While Black Caviar heads for the Diamond Jubilee Stakes, a run for Frankel in the Queen Anne Stakes at same meeting is the preference of Henry Cecil.
Speaking on his website, www.sirhenrycecil.com, the trainer said: "Over the last two seasons he has come on a good deal from his first race and hopefully he will do the same this season.
"He has strengthened and grown up a great deal mentally. All being well his next start will be at Ascot in either the Queen Anne or the Prince of Wales's, the former being my first preference at the moment, but we will see."
Cecil also reiterated his thanks to his staff after Frankel overcame an injury scare last month, and to Mongan and his regular lead-horse and pacemaker Bullet Train.
He said: "After the hold-up in his training schedule at a crucial time it was wonderful to get him there on the day to win.
"Shane Fetherstonhaugh and all those involved with him have done a great job and his success is down to team-work.
"I am very grateful to them all and to his lead-horse and three-parts brother Bullet Train who also fulfils such an important role.
"For a middle-distance horse he did very well to finish fourth."