MICHAEL SCHUMACHER served notice that 1996 may not be a Williams walkover by holding the fastest time around the Buenos Aires racetrack for all but the last five minutes of yesterday's two free practice sessions for tomorrow's Argentine Grand Prix.

Damon Hill knocked the Ferrari driver from his perch in the dying minutes of a session which saw the McLaren driver Mika Hakkinen end up in third place, while Jordan driver Rubens Barrichello was seventh fastest.

Eddie Irvine struggled to achieve 12th best time, as the second Jordan car of Martin Brundle languished in 17th place overnight.

Yesterday's two one hour sessions do not count for grid positions, but they are an important indicator of speed, while they set the tone for this afternoon's door die, one hour official practice session.

Damon Hill, with a 100 per cent win record so far this year, is in top form and likes the Argentinian circuit. "There are a lot of slow corners but it's quite a technical track and not easy to do right," said Hill. He can say that again as nearly all the leading cars spun off the damp dusty and exceptionally bumpy track.

Schumacher was virtually top of the time sheets for all of yesterday's sessions. "This track suits our car a lot more than Brazil," he said, "but it is not easy to be fast and neat here. I went off and Damon and many others also" he said.

The only leading contender not to end up in the gravel was Rubens Barrichello. Eddie Jordan was not disappointed with his seventh place. "Today our main focus was to get a good race set up with a lot of fuel on board. We are only allowed seven sets of new tyres all weekend, and in the afternoon session we decided not to use any new sets. I think Ruby (Barrichello) will go well tomorrow.

Martin Brundle, who said the track was the worst Grand Prix circuit he had ever driven ("no decent fast corners"), couldn't get into a rhythm and had to settle for 17th fastest after he had done his quota of 30 laps for the day. After two disappointing races so far, the English driver will be expected to show form tomorrow.

While Schumacher was battling to be fastest, poor Eddie Irvine was manhandling his bucking bronco of a Ferrari around the narrow track. "It's quite a handful. I went off in both sessions with no damage fortunately. I was fourth on the grid here last year with Jordan and I want to qualify up there this year." That will be no easy task for the Ulsterman.

One of the surprises yesterday was the speed of the McLarens. David Coulthard was second fastest in the morning, while Mika Hakkinen was third fastest in the afternoon.

The team added a bit of James Bond intrigue with the announcement that one of the crates carrying their latest Mercedes V10 had been opened en route to Buenos Aires and the variable inlet trumpet mechanism had been interfered with. The team believe they were victims of a spot of industrial espionage.