The jury is out as to just how effective Mercedes' new sidepod-laden 'B' car really is.

Both Lewis Hamilton and George Russell were on the podium behind Red Bull's dominant Max Verstappen in Barcelona.

"At the end of the day they were 23 seconds behind," said Red Bull boss Christian Horner. "But they still took a step forward.

"It was a big package they introduced but we'll have items later in the season. But I think they will start to put pressure on us in the second half of the season."

Former Ferrari and Bridgestone engineer Kees van de Grint, however, is not so sure.

"If you calculate the percentages, the gap is still the same," he told Viaplay.

"Last year, we also saw that Mercedes was much better on circuits with high-speed corners. I think it could be disappointing again in Canada," said the Dutchman.

However, Mercedes' step forward in Spain displaced the usual main occupant of the podium behind Red Bull - Aston Martin.

"They (Mercedes) had a rocket today," the team's Lance Stroll said after the Spanish GP. "I expected we'd have the pace today but we just didn't."

But Fernando Alonso, with his string of earlier podium finishes in 2023, said he's "not worried".

"We'll strike back in Canada," said the Spaniard. "Qualifying was our Achilles heel here."

Former F1 driver Ralf Schumacher said Mercedes' 'B' car is obviously better, meaning the Brackley based team has the best chance of "annoying" Verstappen "here and there".

"I think there's more potential in the fresh Mercedes package," he told Sky Deutschland, "but the question is how much more money can Mercedes spend on it."

However, he thinks the step forward represented in Spain showed on the face of seven time world champion Hamilton.

"Lewis seems to get along with the new concept a little better than George Russell," said Schumacher, "but he also just seemed a lot happier.

"He seems relieved and sees light on the horizon again. I felt the optimism that had left him for a while. Now he's back."