FP1: Bottas leads Verstappen in close opening practice session at Portimao

Valtteri Bottas and Max Verstappen traded places at the top of the charts throughout FP1, but it was Bottas who ended up narrowly fastest in the first session of the 2021 Portuguese Grand Prix.

Bottas equipped his W12 with soft tyres with 20 minutes remaining and set the benchmark time, improving to an eventual fastest lap of 1m19.648s. Verstappen, who arrived at Portimao with an upgraded RB16B car, developed a flat spot on his tyre late in the session and said his car was "impossible to drive" thanks to the vibrations. Despite that, the Dutchman finished just 0.025s off Bottas on soft tyres.

READ MORE: Another race into the unknown – Why it’s all to play for between Mercedes and Red Bull in Portugal

Lewis Hamilton finished fifth, three-tenths down by the chequered flag on the same C3 soft compounds. The reigning champion was beaten by Ferrari's Charles Leclerc (P4) by under a tenth of a second.

That left Red Bull's Sergio Perez, who ran an aero rake early in the session – possibly testing the team's new parts – in third place, 0.198s off Bottas' pace.

AS IT HAPPENED: Follow all the action from first practice for the Portuguese Grand Prix

AlphaTauri's Pierre Gasly finished sixth, and Saturday star George Russell finished a surprise seventh for Williams, beating eighth-place Ferrari driver Carlos Sainz to the position. It meant McLaren's Imola podium-sitter Lando Norris finished ninth, closely followed by Alpine's Esteban Ocon who rounded out the top 10.

Aston Martin's Lance Stroll was next up in 11th, just ahead of 12th placed Daniel Ricciardo of McLaren. Stroll's team mate Sebastian Vettel finished 16th, his session blotted only by a brief stop in McLaren's pit stop halfway through.

READ MORE: ‘We’ll see the cars being pushed to the max’ – Drivers positive on ‘intense’ Sprint Qualifying plan

Fernando Alonso was the only driver to begin the session on softs – rivals waiting for the 30-minute mark to do so – and Alpine's two-time champion unusually set his fastest lap on hard tyres to go 14th overall, behind AlphaTauri's rookie Yuki Tsunoda.

2020 Formula 2 Championship runner-up Callum Ilott replaced Antonio Giovinazzi at Alfa Romeo for FP1. Ilott, who is now Alfa Romeo's official reserve driver, finished 17th in his FP1 debut. Kimi Raikkonen in the other Alfa Romeo was just four-tenths faster and finished 15th, the two split by Vettel.

While Williams' Russell was up in seventh, his team mate Nicholas Latifi was 19th overall. He split the two Haas drivers, with Mick Schumacher in 18th and Nikita Mazepin 2.3s slower than his team mate to round out the standings in 20th.

READ MORE: PORTUGUESE GRAND PRIX – all-new digital race programme

So with Verstappen just a whisker behind Bottas it looks like we could have another titanic Mercedes vs Red Bull battle this weekend at Portimao.

FP2 follows at 1500 local time with all to play for in Portugal, and live coverage and reaction right here on F1.com.