At the Abu Dhabi Grand Prix last weekend, Verstappen crossed the line in second place to take his ninth podium finish of the year, ending the season third in the drivers' championship behind both Mercedes drivers.
The Dutchman has three race wins to his name in 2019, the most he has ever achieved in a single season during his four year stint with Red Bull.
"Could one ask for more from Max Verstappen?" Brawn pondered in his post-race column. "That would be hard, because, in his fifth year in Formula 1 he finished the championship in the top three for the first time and enjoyed an excellent season overall.
"Max scored the first pole position of his career in Hungary (and then a second in Brazil) and took three wins during the season to take his career total to eight."
Brawn added that he impressed with the lack of on-track errors that Verstappen produced this year, which he was arguably prone to in previous years with Red Bull.
"Perhaps more significantly we saw fewer mistakes, which in the past have mainly been due to his impatient nature," Brawn wrote. "Those episodes of hot-headedness have cost him dearly in previous seasons but this year rash moments were few and far between."
With Lewis Hamilton ending the 2019 season with a sixth world championship to his name, Brawn firmly believes that Verstappen is now in a position to challenge the Briton.
"The Red Bull youngster, who only turned 22 a couple of months ago, is now undoubtedly in the most clinical form of his career to date and is now ready to challenge Lewis Hamilton.
"Of course he needs a car capable of doing that, which was not the case in the early part of this season.
"However, the Red Bull-Honda partnership took a number of steps forward during the season and is now beginning to produce results that suggest they will be fighting for the championships in 2020."
Bahrain International Circuit - Winter testing