Ahead of today's opening practice session the air temperature is 24 degrees C and the track temperature is 29 degrees.

This week we finally get to see Pirelli's supersoft tyre which will be run as well as the soft (prime) tyre. The Italian manufacturer says the supersoft is only good for one really hot lap, consequently it is thought we will see the twelve teams adopt a range of different strategies. Pirelli also insists that marbles will not be so much of a problem here as in previous races.

Prior to this weekend, the supersofts have only ever been used in the second pre-season test in Barcelona.

After days of dithering, the FIA has given the OK for the use of DRS here - it can be used on the main straight only on Sunday - but its use is not permitted in the tunnel. Most drivers still believe that its use anywhere her could cause problems, therefore the sport's governing body has said if there are problems it will review the situation.

While overtaking is nigh impossible here, there are none of the fast corners that suit Red Bull and McLaren is sounding mighty confident. Sadly, the same cannot be said for Ferrari.

Other than the usual problems that need to be faced here, a truck fire on Tuesday night meant that new asphalt had to be laid at the notorious Ste Devote, a slippery corner at the best of times.

The only reserve driver running in this session is Ricciardo, the Australian being given Alguersuari's car, thereby adding to the pressure on the young Spaniard.

The lights go green and Kovalainen leads the way, followed by d'Ambrosio, Ricciardo, Trulli, Petrov and reigning world champion, and world championship leader, Sebastian Vettel.

A previous winner here, Trulli, like Perez, stays out for a second installation lap.

Five minutes into the session all but the Mercedes duo have been out.

While most teams have brought upgrades here - as is usually the case at Monaco - only Ferrari and Renault appear to be running them today, both sporting revised rear wings.

Unlike previous races, today there are no extra sets of tyres available - only two sets of prime (soft) and one option (supersoft).

With the Mercedes duo having finally completed their installation laps, we enter a long phase of total inactivity, other than the odd wave to the crowd or a nod to the camera.

Fifteen minutes into the session, Karthikeyan is the first driver to come out for a second run. With his team threatening to protest the majority of its rivals this weekend, the Indian can possibly sense a handful of points. Then again, maybe not.

Button joins the Hispania driver on track, only to dive into the pits, at which point teammate Hamilton comes out for another quickie.

Karthikeyan posts the first time of the day, the Hispania driver crossing the line at 1:38.718. Next time around the Indian improves to 32.260 - the other 23 drivers look on.

As Karthikeyan steadily improves - raising the benchmark with a 27.772 - Perez heads down the pitlane. Twenty-six minutes of the session gone and only one name on the timesheets.

Understandably, Perez goes straight to the top of the timesheets, the Sauber driver, who scored his first F1 points last weekend, crosses the line at 23.206. Karthikeyan improves to 26.043.

D'Ambrosio is the third driver to post a time, the Virgin driver stopping the clock at 30.989 as Perez, who goes quickest in the first two sectors, loses time in the third after a massive lock up.

As Karthikeyan returns to the pits, having completed 13 laps, Maldonado, Liuzzi, di Resta and Kobayashi get to work.

Race Control warns that there is water on the track towards the end of the pit straight. That said, it is unclear where the water is coming from. Back in the 80s there were problems one weekend when water poured on to the track in the tunnel after the fire sprinklers went off in the Loews Hotel kitchen above the tunnel.

A 21.902 sees Maldonado go quickest, ahead of Kobayashi (22.630), Perez, di Resta, Liuzzi, d'Ambrosio and Karthikeyan.