By Andrew Benson Motorsport editor

Alonso had to withstand the toughest pressure from Schumacher

If there were any doubts about Fernando Alonso's ability to sustain a season-long challenge for the Formula One world championship, he surely erased them on Sunday.

The Spaniard's drive to victory in the San Marino Grand Prix was overshadowed by Michael Schumacher's sensational recovery.

But Alonso's performance underlined just why the Renault star will be such a tough nut for Schumacher to crack this season.

It is not just that Alonso has extended his championship lead over Schumacher to 26 points with his third win in succession; it was the manner of his Imola victory that was so telling.

Alonso described it as his "best win in F1 so far" - a revealing remark in more ways than one.

This is probably as tough a challenge as Michael has faced Ross Brawn Ferrari technical director

Firstly, it shows he is aware how important it was to put down a psychological marker to Schumacher at the beginning of what is going to be a long, hard battle.

But it also reveals that Alonso knows he can get even better than this.

Still only 23, Alonso showed incredible maturity to fend off a much faster car for the last 13 laps while also protecting an engine that had been severely strained in the heat of Bahrain three weeks ago.

And where Jenson Button wilted under Schumacher's pressure, hesitating while lapping backmarkers and allowing the veteran to slip through, Alonso was flawless.

Profile: Fernando Alonso

It proved why many people in F1 have long thought that for all the ability of Kimi Raikkonen, Juan Pablo Montoya and Button, it is Alonso who is likely to emerge as the leader of the new generation of drivers.

As he watched Alonso build up his massive lead in the first three races of this season, Schumacher would already have been aware of the huge task facing him.

These two have "previous" - they staged a number of battles in 2003, the last season in which Schumacher had to struggle, and some of them took them into very dangerous territory.

Alonso will be a tough nut for Schumacher to crack this year

Most striking was the violent lunge Schumacher made at Alonso on the first lap of the British Grand Prix, putting the Renault on to the grass at 200mph.

It is a move Alonso has not forgotten, and for which one day there will almost certainly be payback.

But there was more in it than just a driver defending his place - Schumacher, recognising that this was a man who was going to cause him trouble in the future, was trying to stamp his authority on the emerging star.

Alonso's performance on Sunday showed that, where the German has been able to intimidate many of his rivals, it has singularly not worked on this hard little man from Oviedo.

Have your say Can Alonso fend off Schumacher?

"This is probably as tough a challenge as Michael has faced," Ferrari technical director Ross Brawn said after Sunday's race.

"Fernando is driving extremely well, much better than we've seen before. I think he is going to be a very tough guy to beat this year."

With such a lead, that is undoubtedly the case, for F1's latest points system - introduced in 2003 - makes it especially difficult for drivers to close big gaps in the championship.

The new Ferrari showed stunning speed at Imola

All the same, Schumacher's electrifying pace at Imola suggested that he is going to win many races this year.

The new Ferrari is clearly a superb car - quite probably the class of the field - but even so it is unlikely to be more than a second a lap faster than anything else for the rest of the season.

For one thing, Renault had reduced the revs on Alonso's engine, knowing that it was vulnerable having already done one full race distance in Bahrain.

Schumacher, who retired in Sakhir three weeks ago, had no such restriction under F1's new two-race engine rule.

F1's new rules explained

For another, Ferrari's advantage was exaggerated because most of the teams using Michelin tyres, like Renault, ran into problems as their rubber did not respond well to the cool conditions at Imola.

And the one Michelin team that did not have that problem, McLaren, would easily have won the race had Raikkonen not retired with a driveshaft failure after nine laps.

Raikkonen led convincingly from the start at Imola only to retire

Ferrari's Bridgestones, by contrast, performed superbly, suggesting the Japanese company has solved some of the problems that afflicted it in the first three races.

Reliability problems aside, McLaren finally showed the form they have been threatening all season and are likely to be potential winners everywhere from now on.

Add in a resurgent BAR, newly-fast Toyota and the promise of better things from Williams and 2005 could repair much of the damage done to F1 by years of mind-numbing Ferrari domination.