Hamilton chases 100th pole in Portuguese GP qualifying

But the Mercedes star cannot afford another mistake as two weeks ago in Imola if he wants to keep his fast Red Bull rival at bay, DPA reported.

Hamilton won the season-opener in Bahrain ahead of Verstappen before the Dutchman turned the tide in Italy, with pole-sitter Hamilton riding out in a rare mistake after which he still managed to rebound from ninth to second at the chequered flag.

Red Bull ruled F1 with four straight drivers' and constructors' titles 2010-2013 before Mercedes became unrivalled in the following years by sweeping all trophies on offer - including six of the drivers' titles for Hamilton.

Mercedes's total dominance has helped Hamilton to his extraordinary record of pole positions and race wins which stand at 99 and 96 respectively heading to Portimao where he won from first on the grid last season.

But Red Bull are re-emerging as a major threat and according to their advisor Helmut Marko this also contributed to Hamilton's mishap in Imola.

"They didn't have continuous opposition, but that's now the case with Red Bull and Max Verstappen," Marko told broadcasters RTL.

"And apparently - humanly understandable - that leads to reactions. That means we have to keep up the pressure constantly, if not increase it."

Long-time Red Bull team principal Christian Horner also hopes that the great start will boost them for the season with a record 23 races.

"It's by far the best start we've had for quite a few years," Horner said. "We just want to build that momentum and keep that all the way through the year."

Verstappen and Hamilton have both said they welcome the fight for supremacy, with Hamilton naming his mistake in Italy "a lesson" for the future as he seeks a record eighth title.

"It's great to be fighting against Lewis, Mercedes who have been so dominant and they're very difficult to beat," Vestappen said, adding that being "very, very competitive" in both races was "very promising but no guarantee."

Hamilton said: "I think this is really the first time in a long time that Red Bull have had a championship-winning car, so I think it's going to be close all the way through the year - and it's just going to be, hopefully, more and more of these battles."

Looking at Portimao (and beyond) Mercedes motor sport chief Toto Wolff said: "We're expecting another close fight with Red Bull, and both McLaren and Ferrari could also be in the mix too."

Lando Norris was an impressive third for McLaren in Imola and Charles Leclerc followed in fourth for Ferrari, with both teams keen to follow up on that in Portimao.