Day 1 of F1 pre-season testing in Barcelona

Sebastian Vettel was at the Circuit de Catalunya for the first of eight test days over the next two weeks. Ferrari's German star laid down the morning's fastest laps. On the subject of fast, 2017's rule changes do appear to have upped the pace. Even on the first morning shaking down brand new cars, the front-runners were close to the 2016 pole position lap at the same circuit.

Meet the driver with the most improved prospects for 2017. After four solid seasons with Williams, Valtteri Bottas takes Nico Rosberg's place in what's been the car to beat of late - he pounded out quick, consistent laps without incident. The number 77 driver, an allusion to the twin T's in both his names, has two second-place finishes on his Grand Prix CV - he'll aim to go one better now.

Testing's the right time for a car to have teething troubles. Still, Red Bull's Daniel Ricciardo might have hoped to lay down more than four laps before his RB13 ground to a halt. The car's online launch had the slogan "Break Superstition" and its release video shunned lucky symbols like rabbits' feet and four-leafed clovers. You know what they say about tempting fate.

McLaren pleased fans with longer memories when it unveiled its first car in decades to use is signature orange color of old. But will this year's Honda-powered car perform too? It could have begun better. Fernando Alonso went out with aerodynamics sensors behind his front wheels, looking for performance data. But an oil systems problem meant an immediate return to the pits for hours of repairs.

Felipe Massa didn't expect to be testing again this year. Until Nico Rosberg's shock retirement, it was Massa readying himself to leave the pit lane. But when Valtteri Bottas joined Mercedes, Williams found themselves with a vacancy alongside unproven teenager Lance Stroll - meaning a steady, experienced pair of hands would be preferable. Who better than the veteran walking out of the door?

Nico Hülkenberg left Force India after the team's best year to date in the sport. His bold move was to switch for Renault - a team with more history, standing, and probably a bigger budget, but one that has really struggled in recent years. With more support from Renault itself, and with the Hulk at the controls, can the team recapture past glory?

The 2017 field, even the lowly Sauber, promises to lap faster than in recent years. That's to do with the far-reaching regulation changes for the new season. Tires are wider (and supposedly grip better) to try to increase cornering speed, and the narrow front and rear wings of recent years have been broadened out. The goal is increased lap time, but also better racing. Are they one and the same?

One design solution several teams have turned to will be familiar to regular viewers. Back again are variations on the "shark fin" appendage above the engine covers, popular in 2010. Its purpose is to funnel air - which entered the car at a hole nearer the front - onto the rear wing. Romain Grosjean and Kevin Magnussen will hope it gives Haas F1 an edge.

The Mercedes-powered Force India sports a shark fin too, and Sergio Perez was putting miles on the VJM10 on Monday. Force India finished fourth - their best ever - in the 2016 constructors' championship. Can the Silverstone-based outfit punch above its weight once more with Perez and French youngster Esteban Ocon at the wheel?

Toro Rosso sent Spaniard Carlos Sainz out in front of the home fans on the first day's testing. Sainz is part of an unchanged line-up at the Red Bull junior outfit, he'll race alongside Daniil Kvyat in 2017. Toro Rosso have switched engines for this season - moving back to Renault after Red Bull fared better than feared last season. The Italians had been using year-old Ferrari motors instead.