Fernando Alonso said Michael Schumacher was the greatest rival of his career as the Spaniard prepares to bow out of Formula One.Alonso, 37, will start his 312th and final grand prix in Abu Dhabi on Sunday.His 18-season F1 legacy will be divided into two parts: one where his remarkable race craft enabled him to win 32 times, beat arguably the greatest in Schumacher, and claim back-to-back world championships.The other will have him judged as a divisive, and poorly-advised driver, who made a catalogue of wrong career moves.Alonso was also implicated in two of the sport’s darkest days, the so-called Spygate scandal of 2007 – where his then-McLaren team were discovered to have 780 pages of Ferrari technical details – and Crashgate, a year later.Renault hatched a plan for Nelson Piquet to crash in Singapore, allowing Alonso to claim the most unlikely of wins. The Spaniard has always denied any wrong-doing.Following his title-winning triumphs at Renault, Alonso fell out with Hamilton during one fractious year at McLaren. A move back to Renault followed, before five fruitless seasons at Ferrari, and a second woeful spell at McLaren.He will retire without a victory in more than five years, without a podium finish in more than four, and heads into Sunday’s race 10th in the championship, sandwiched between Kevin Magnussen and Esteban Ocon.

Remarkably, Hamilton has scored more points in his last seven races than Alonso has managed in four years.

Who would have thought that when the fresh-faced Briton was thrown alongside Alonso, who had just beaten Schumacher to two successive titles, nearly 13 years ago?

“If I have to say who my greatest rival was, it will be Michael,” Alonso said on the eve of the season-concluding race.

“When I was go-karting, Michael was winning. When I was in the junior categories, Michael was winning. When I got to Formula One, Michael was dominating. Then, I found myself fighting wheel-to-wheel with him. Those battles were definitely special, and emotional.”

The great and good of F1 will throw a paddock party in Alonso’s honour on Saturday evening. Next year, he will set his sights on matching Briton’s Graham Hill by winning the Indianapolis 500 – to add to his victories in Monaco and Le Mans – and complete the ‘Triple Crown’.

Alonso insisted here that his grand prix career may not be over, but it is highly unlikely he will sit in a Formula One cockpit again.

“It is difficult to think about coming back, but the door is not closed,” he added. “I don’t know how I will feel next year because I’ve been doing this for my whole life.

“There are negative aspects to Formula One. If you are here for 18 seasons, you have to dedicate your entire life to it. You have no friends, no family, no free time, no privacy, no wife, no kids, no nothing. It is just full dedication if you want to succeed.

“Maybe by April or May, I am desperate, on the sofa, so I find a way to somehow come back. But that’s not the idea.”