Alonso went head-to-head for the title with Schumacher in the German’s final year with Ferrari.
Alonso, driving for Renault at the time, ultimately came out on top in a dramatic end to the season.
Before that, Alonso and Schumacher shared a number of battles as Ferrari’s dominance ended, while Renault enjoyed an upwards trajectory.
Speaking in an interview on Aston Martin’s website, Alonso reflected on his rivalry with Schumacher, explaining what he learnt from him.
“Michael didn’t have bad days,” he said. “Michael never underperformed. “That’s what impressed me most when I got to Formula One and especially when I fought with him for the championship.
“Previously, in all my career and different categories, my rivals had some bad days and those were the days when you would capitalise – you would score many more points than them. With Michael, that didn’t happen. He and Ferrari were unbeatable most of the time, but even when they didn’t have the car, the tyres, or whatever working in the right window, Michael still finished second or third.
“Even after a bad free practice or a bad qualifying, you would still find Michael on the podium on Sunday. He had this tenacity, this willingness to exploit any opportunity – to minimise the damage on the bad days and maximise the good days. His determination was outstanding.”
Alonso was also asked if he thought he was the best driver in F1.
He replied: “Nobody knows the answer to that question. Every season we keep changing opinion.
“We thought for many years that Michael Schumacher was unbeatable and had maybe reached a level that no one had in the history of F1.
“But, throughout the history of the sport, we’ve seen different drivers dominating – it’s impossible to compare them.
“What I do know is that I always try to give my maximum. I’m never demotivated. It doesn’t matter whether I’m fighting for fifth or 15th, for me, it’s like fighting for the win because I have to make sure that I give 100 per cent on every lap of every race.”