Max Verstappen edges Sainz and Vettel after first in-season F1 test day

Red Bull's Max Verstappen posted a late lap on the supersoft tyres to narrowly beat Renault's Carlos Sainz and Ferrari's Sebastian Vettel to the top spot on the first day of F1 2018 in-season testing.

Less than two days after the conclusion of the Spanish Grand Prix, all ten Formula One teams were back on track at the Circuit de Barcelona-Catalunya for the first of four official in-season test days, with the majority of teams completing well over one hundred laps of the track.

Fresh from his first podium of the season at the weekend, Verstappen completed 148 laps en route to posting the best lap time of the day - a 1:17.528. However, this lap was several tenths off the pace of his fastest qualifying lap time from the weekend.

Sainz had been on course to land end the day fastest. He set his best lap of the day with just under two hours to go on the Pirelli hypersoft tyre, the street racing tyre that will be used in Monaco next week, but his lap time was beaten by a mere 0.034 of a second.

Prior to Sainz's hypersoft effort, Vettel had been heading the time sheets. Equipped with the standard soft tyre, Vettel registered a 1:17.659, but his effort ultimately fell 0.131 behind Verstappen's late effort.

Part-way through the day, Ferrari confirmed through Twitter that they had been running both versions of the Pirelli tyres. These were the newer, thinner tyres used for the Spanish Grand Prix weekend (and will be used again at Paul Ricard and Silverstone) and the original tyres used in the first four races of the season.

Ferrari also revealed after the test that Vettel's best lap was set on the original tyres, the ones which weren't used at the Spanish Grand Prix. They had made it clear during the weekend they weren't I favour of the thin gauge product, but Vettel said after having the rare chance to back to back the tyres, that the Pirelli decision had been the right one and he would have struggled more on Sunday with the original gauge tyres.

Following his disastrous start to his Spanish Grand Prix, Romain Grosjean completed a much-needed day of solid running. He set the fastest time of the morning session of hypersoft tyres, which remained his best time for the rest of the day as he clocked up 136 laps for Haas.

Force India's Canadian reserve driver Nicholas Latifi - who was forced to miss out on pre-season testing due to an illness - was given his first run-out in the VJM11 ahead of his free practice debut at the Canadian Grand Prix next month.

He made a series of improvements over the final hour to set the fifth-fastest time of a 1:18.530 on the hypersoft tyres.

Sixth-placed Lewis Hamilton set his best time in the morning session on soft tyres, which remained his fastest time in the afternoon. The Briton racked up the most mileage of any driver, completing 151 laps, well over two Spanish Grand Prix race distances.

The Mercedes car was fitted with a new rear lighting system during the opening day. As well as the usual red light at the back of the car - which is used in wet weather and signify if a car's power unit is 'derating' - the rear wing end plates were extended and fitted with thin strips of LED lights.

This was at the request of the FIA, who are looking into an alteration of the rear light to improve visibility. However, due to the sunny conditions in Barcelona, the FIA may consider retesting on a day when conditions are worse.

Stoffel Vandoorne was one of only two drivers to complete the full day and not register one hundred laps. However, without any noticeable problems occurring for the team, his best lap was a 1:18.981 and he completed 85 laps of the circuit.

Antonio Giovinazzi caused a late red flag by pulling over at the chicane, but otherwise it was a blemish-free day of running for Sauber, who completed 135 laps. Giovinazzi will take over from Sebastian Vettel at Ferrari for day two of the test tomorrow. He is one of the drivers putting pressure on Romain Grosjean for his Haas F1 seat.

Oliver Rowland completed his first outing for Williams since his switch from a development driver role at Renault at the start of the season.

He made improvements throughout the day and clocked a 1:20.009 on supersoft tyres in the afternoon session. He will make way for Robert Kubica to return to the cockpit tomorrow.

Lando Norris, George Russell and Oliver Turvey were given fresh opportunities to sample Formula One machinery with both McLaren and Force India undertaking Pirelli testing duties.

The Pirelli tests (on unmarked tyres) meant that the two teams were permitted to use two cars for the test. Norris and Turvey had half-a-day each in the McLaren, whilst Russell had a full day in the Force India.

Norris was the fastest of the Pirelli testers in tenth place with a 1:20.997, whilst Russell ended the day eleventh with Turvey thirteenth.

Sean Gelael separated the cars equipped with experimental Pirelli rubber. The Toro Rosso team swapped the car's Honda power unit as a precaution to a chassis issue which developed part-way through the day, meaning they only completed 50 laps.

IN-SEASON TEST DAY ONE (BARCELONA) RESULTS

1 Max Verstappen Red Bull/Renault 1m17.528 147 laps

2 Carlos Sainz Renault 1m17.562 119 laps

3 Sebastian Vettel Ferrari 1m17.659 136 laps

4 Romain Grosjean Haas/Ferrari 1m18.449 129 laps

5 Nicholas Latifi Force India/Mercedes 1m18.530 107 laps

6 Lewis Hamilton Mercedes 1m18.543 151 laps

7 Stoffel Vandoorne McLaren/Renault 1m18.981 85 laps

8 Antonio Giovinazzi Sauber/Ferrari 1m19.693 135 laps

9 Oliver Rowland Williams/Mercedes 1m20.009 121 laps

10 Lando Norris McLaren/Renault 1m20.997 76 laps

11 George Russell Force India/Mercedes 1m21.478 123 laps

12 Sean Gelael Toro Rosso/Honda 1m21.935 50 laps

13 Oliver Turvey McLaren/Renault 1m23.070 58 laps

All Images: Motorsport Images