The Formula One tour heads to Barcelona for the opening round of the European season this weekend.

Valtteri Bottas leads Mercedes team-mate Lewis Hamilton by one point in the championship standings following the Finn's win at the last round in Azerbaijan.

Here, Press Association Sport looks at the key talking points ahead of Sunday's race.

Ferrari hoping to rescue season with engine upgrade

Sebastian Vettel and Charles Leclerc will be bidding to end Mercedes' dominant start to the season in Barcelona. The Ferrari duo have already fallen 35 (Vettel) and 40 (Leclerc) points adrift in the championship race, and failure to win again this weekend will serve as another blow to the Scuderia's title hopes.

The Italian team have brought forward an engine upgrade, originally scheduled for next month's race in Canada, in hope that the extra power boost will help them stop the rot in Barcelona. Ferrari were quickest in pre-season testing at the Circuit de Catalunya, and they need a repeat of that form to relaunch their failing title push.

A word of warning, however. Hamilton, who was at New York's glitzy Met Gala on Monday night, has won the last two races in Spain, while Ferrari have not tasted victory in Barcelona since Fernando Alonso triumphed for them six years ago.

Hamilton's Mercedes sceptical despite record start

Such has been Mercedes' faultless start to the new campaign, they will arrive in Spain 74 points ahead of Ferrari in the constructors' race.

Their dominant results, however, do not paint an entirely accurate picture. Leclerc should have won in Bahrain, but suffered an engine failure. Ferrari were in a strong position in Baku, too, until Leclerc crashed in qualifying.

Credit to Mercedes for taking advantage of Ferrari's mishaps, but team principal Toto Wolff is wary of their title  advantage. "We remain quite sceptical of our own performance," said the Austrian. "Our opponents were blisteringly quick in winter testing, so the Spanish Grand Prix will be anything but easy."

Can Verstappen stay in championship fight?

In contrast to his troubled start to last year, Red Bull's Max Verstappen has delivered a mature opening to the new campaign. He has finished third, fourth, fourth and fourth, to sit behind Bottas, Hamilton and Vettel in the standings, just one point adrift of the Ferrari driver.

Verstappen's Red Bull has not been a match for Mercedes and Ferrari, but the young star deserves praise for staying in the mix. And with Red Bull set to take an upgraded package to Barcelona, Verstappen could now be in a position to challenge the sport's big two.

Norris shows off new company car

Another driver who can be happy with his start to the year is Lando Norris. The British rookie, 19, has scored double the points of his team-mate Carlos Sainz after the opening four rounds.

Norris posed with his new company car – a £175,000 orange McLaren 570s Spider – ahead of the Bank Holiday weekend. "You're not going to miss me in Tesco's car park with this," he wrote on social media.

Race to mark 25th anniversary of Senna's death

The organisers of the Barcelona race will pay tribute to Ayrton Senna and Roland Ratzenberger, the two drivers killed at the San Marino Grand Prix a quarter of a century ago.

A half-Brazilian, half-Austrian flag will be awarded to the winner of Sunday's race. The combined flag will also be at half-mast on the entrance to the track. A life-size bronze sculpture of Senna, created by the British artist Paul Oz, will be on display at the circuit, too.