Lewis Hamilton extended his lead in the drivers' World championship to 17 points on Sunday when he roared to an imperious victory as Mercedes scored a one-two at the Spanish Grand Prix.
While on the day Vettel was probably not a realistic winning chance, second place - rather than his eventual fourth placing - had been eminently achievable.
Vettel put their drop in form down to three things: speed, tyres - referring to the change in tread depth for this specific race - and reliability. They changed but they changed for everyone.
Despite the early problems this season, Mercedes will arrive in Monaco with Hamilton leading the drivers' standings by 17 points over Vettel.
"I'm always on the worrying side and we'd been very good in winter testing here and when we went to Melbourne everybody said it was going to be an easy Mercedes one and then we had hard races so I think we were very good today but we need to stay calm and humble", Wolff said. Kimi (Raikkonen, Vettel's team-mate) had an issue with the engine (on Saturday) and had to change it.
But Mercedes team boss Toto Wolff says he "fully understands" his rivals' decision. It was a disappointing weekend for Ferrari which also featured a concerning engine failure for Kimi Raikkonen in the other auto during a season where engines are more restricted than ever before in the V6 turbo era.More news: 'Tax Amazon': Seattle passes plan for corporate wealth tax to fund housing
He now has 95 points to Vettel's 78 after five rounds of the 21-race championship.
But a delay in the pits to allow Sergio Perez past to avoid an unsafe release cost Vettel a podium, while second was essentially lost because of tyre wear.
"We definitely go to Monaco on a high note, but we know that we still have a lot of work to do". Daniel Ricciardo (Red Bull) + 50.058; 6.
Despite the Ferrari driver's fresher tyres, and the fact that Verstappen had damaged his front wing when he hit the rear of Lance Stroll's lapped Williams at the VSC restart, Vettel was unable to dislodge the Dutchman from the final step of the podium.
"It felt good. It was the closest I've been to feeling it is all going right, but there are still things that are not quite flawless". All three cars suffered heavy damage and the race was immediately brought under the control of the safety vehicle. A small mistake after the lap 1 safety auto compromised the early phase of the grand prix, but even with an offset strategy Red Bull couldn't unlock the true potential of the vehicle to challenge Mercedes, which is a disappointment considering Ricciardo recorded the fastest lap of the grand prix - proving that the RB14 does have intrinsic race pace. Ricciardo was followed by Haas" Kevin Magnussen - strengthening belief (yet again!) - that his team is the "best of the rest' and if they string a race together, a good result is possible. Carlos Sainz finished seventh in his Renault, with Fernando Alonso taking eighth. His finish helped Haas jump up to 6th place with 19 points, one ahead of Force India.
The 2018 Spanish Grand Prix further highlighted two things.