In the gap between the Monaco and Canadian grands prix, a minor motor racing miracle played out as Robert Kubica delivered a sensational performance in testing the Renault team's old Lotus E20 F1 car at the Valencia track.

After six years away from an F1 cockpit (or a single-seater of any sort) and with a permanently disabled right arm from his rallying accident, by the team's description he simply took up where he had left off, drove as if he'd never been away. Just a week before his rallying accident in January 2011, he had set the fastest time at the F1 winter test at this very circuit.

Six years on, he completed 155 laps, pretty much flat-out the whole way, out-paced the team's quick junior driver Sergey Sirotkin (who was in the car the previous day) and identified the key areas of the car's weaknesses.

Robert Kubica talks to Sky Sports F1 about his possible return to Formula 1 Robert Kubica talks to Sky Sports F1 about his possible return to Formula 1

You may well have seen his social media video in which he confirmed he felt he'd reached much the same level as before - and that it is his wish to come back to F1.

Should he be successful in this aim and, particularly, should his performance in the test be replicated in grands prix, this would be one of the greatest sporting comebacks of all time.

Just how good was Kubica?

Arguably, in a generation that includes Lewis Hamilton, Fernando Alonso and Sebastian Vettel, he was the best of them all.

That, incidentally, was the view of Alonso.

Hamilton regarded him as the best driver he had ever encountered as they made their way through karting and up the junior car racing ladder.

BMW-Sauber didn't put up a big fight when Red Bull reclaimed its junior driver Vettel because Sauber felt that its other driver, Kubica, was so much quicker. Vettel had taken over Kubica's former role of Friday tester when Robert was promoted to the race team mid-way through 2006 because his Friday performances were simply too sensational to keep him out of a race seat, something that hastened Jacques Villeneuve's departure.

In many ways that 2006 half-season was his most impressive of all. On the high-grip Michelin tyres the team was contracted to, he was able to take an outrageous momentum into the corners, overlapping the braking and corner entry phases probably better than anyone else of the time. In his Friday role he was fastest of the field by the outrageous margin of two seconds in Montreal and out on track he looked every bit that. His driving through turns 3-4 that day remain imprinted upon my memory.

It's still visually the fastest I have ever seen anyone drive.

I recall Martin Brundle one day in 2008 coming into the commentary booth after having watched a practice session trackside and saying, "Kubica is pushing about 10% harder through that corner than anyone else," and I knew exactly what he meant.

The story of his F1 career - so far

Although his rookie race performances at the end of 2006 were consistent with his testing form - he was on the podium by his second race - he struggled in 2007.

Michelin had withdrawn from F1 and everyone was on hard-compound Bridgestones. These did not reward his natural technique anything like as well and, initially coupled with an inexperienced engineer, he struggled to get the best from a difficult car. There were still moments of magic, but he was out-scored by the experienced Nick Heidfeld.

But into 2008, with a much better car, the Kubica of '06 reappeared. Against a faster Ferrari and McLaren he was leading the championship after his victory in Canada and would remain convinced for evermore that 2008 was a winnable championship had BMW not switched off development of that car to concentrate on its 2009 'title winner'.

The '09 car was, of course no such thing, the team badly caught out by the new aero regulations as Brawn and Red Bull fought out championship. It was a car that on merit was around the Q1/Q2 cut-off for much of the season. Yet Kubica was in contention for victory in Melbourne until a late race collision with Vettel. In Brazil that year he was running a miraculous second until the engine let go. BMW withdrew from F1 at the end of the year and Kubica transferred to the Renault team for 2010.

His ability to occasionally transcend the level of the car was again apparent. Although the Renault R30 was a much better car than the '09 BMW, it was nowhere near the level of a Red Bull, McLaren or Ferrari. It lacked ultimate downforce but its main asset was a great driveability - and this allowed Kubica to work his magic. At the three premier drivers tracks of the year - Monaco, Spa and Suzuka - he started second, third and third respectively.

In the modern era such things should not have been possible.

At Suzuka the qualifying lap left him afterwards speechless and in a daze, so much of himself had he given, so close to an accident had he been for much of the lap. The team's chief race engineer of the time (now trackside operations director), Alan Permane, recalled: "I've never seen a driver give that much in a lap. That was him - he's totally committed in a way most other drivers wouldn't even understand."

Ferrari had seen enough; it's since been confirmed he'd signed to drive for the Scuderia alongside Alonso from 2013.

Could Kubica make a full comeback to F1?

He's consumed by driving and by cars, in a way that is extreme. His understanding of every facet of the car's performance and his drive to improve everything all the time - including himself - is remarkable.

If his driving had a weakness it was that it was too dependent upon a specific chassis balance which - as with Vettel - made him super-quick at his peak but prone to a sudden fall from the peak if the car or tyres couldn't give him that. In this way he was less adaptable than Hamilton or Alonso perhaps, but with a different combination of qualities could well have been the most formidable of them all.

Kubica, in fact, joined Hamilton's F3 team Manor for the Macau Grand Prix. The two hottest properties in junior racing at the time as team-mates. It was Kubica who stuck it on pole.

Valencia last week suggested we may not have seen the last of him.

MH