Lewis Hamilton raised the bar for this week's Spanish Grand Prix by setting the fastest time in second practice on Friday.
Hamilton was beaten to top spot by his Mercedes team-mate Valtteri Bottas in the opening running, but the reigning champion ended the day fastest at Barcelona's sun-bathed Circuit de Catalunya.
The British driver's best effort of one minute and 18.259 seconds enabled him to edge out Daniel Ricciardo by less than two tenths with his Red Bull team-mate Max Verstappen third.
Ricciardo crashed out of opening practice earlier on Friday after he lost control of his Red Bull at Turn 4 and slid helplessly across the sand trap and into the barriers.
But following repairs to his car, the Australian, backed up by Verstappen, ran Hamilton close to suggest Red Bull have the credentials to take the fight to Mercedes and Ferrari.
Ferrari rarely show their true pace on Friday and Sebastian Vettel, who trails Hamilton by four points, finished in fourth, a third of a second down on Hamilton's best time.
Vettel's team-mate Kimi Raikkonen posted the sixth fastest lap, but was told to park his Ferrari after puffs of white smoke came from his engine. Bottas was fifth in the order.
Mercedes, Ferrari and Red Bull have all brought revised cars to this weekend's race with the opening western European round of the season traditionally kick-starting the development war.
And Bottas's early pace - the Finn posted a record-breaking lap of this 2.9-mile track - followed by Hamilton's time in the second session, would indicate Mercedes have taken the greater stride forward with Vettel's Ferrari team having previously boasted the most complete package of the season.
McLaren had also been hopeful that their revised car would curb a downward spiral, but after Fernando Alonso finished a dizzying sixth by trading times with the Red Bull cars in the day's opening running, he was only 12th in the afternoon session.
Saturday marks the fifth anniversary of the Spaniard's last victory in F1, and it is highly likely that he may never win again.
Stoffel Vandoorne was ninth, but there is still significant work to do for the British team, who have failed to get either of their cars into the final phase of qualifying this season.
Robert Kubica is back competing at his first grand prix weekend in more than seven years after suffering career-changing injuries to his right arm in a rally crash.
The Pole, now acting as reserve driver for Williams, was last but one in the opening sessions, 1.3secs ahead of team-mate Lance Stroll.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here