The history of Formula 1 is littered with generational battles between the established benchmark and the young upstart determined to take the crown for himself.
Some of these (Jim Clark vs Jackie Stewart and Ayrton Senna vs Michael Schumacher) were cut tragically short while others such as Alain Prost vs Senna exploded in a rivalry Grand Prix racing had never seen before - or since.
One such generational battle is playing out at the moment as Lewis Hamilton and Max Verstappen - the two preeminent drivers of this era - go at it for the championship.
In 2021, the white-hot, fierce title battle was only settled in very controversial circumstances in the Abu Dhabi finale in Verstappen's favour, while they also managed to find each other on track and collide again in Brazil 2022 as Hamilton and Mercedes endured a troubled season.
Anyhow, any rivalry needs a first flashpoint - and Hamilton and Verstappen's first came five years ago in the 2018 Bahrain Grand Prix, the venue of the 2023 season-opener this weekend...
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First Hamilton Verstappen flashpoint
Prior to the 2018 Bahrain race, Hamilton and Verstappen had had very little to do with each other on-track.
Sure, Verstappen had overtaken Hamilton in Malaysia 2017 for the win, but the Briton was firmly in 'Win the championship' mode, with later fisticuffs at the start in Mexico also a flash in the pan.
In Bahrain, Hamilton started ninth after a gearbox grid penalty with Verstappen down in 15th following a crash in qualifying.
A cautious first lap and a typically aggressive one from Hamilton and Verstappen, respectively had the two dicing for position at Turn 1 on the second lap.
Verstappen claimed he left Hamilton room, but the left-rear tyre clipped the Mercedes front-wing - and promptly punctured.
He limped back around to the pits, but transmission failure on the next lap put him out of the race.
Hamilton would go onto finish third - but labelled Verstappen a "dickhead" for the move in the cooldown room after reviewing the incident for the first time.
Next blow in next race
Next time out in China, Hamilton apologised for the comment, but taught Verstappen a lesson after the Safety Car restart.
On far fresher tyres, Verstappen tried to overtake Hamilton at Turns 7 and 8, the fast-sweepers in the second sector.
Canny as ever, Hamilton gently opened the steering on Lap 39, forcing Verstappen into the run-off, and crucially position to teammate Daniel Ricciardo.
Ricciardo would go onto a stunning win as Verstappen was left with fifth following a collision with Sebastian Vettel.
It would be over a year until the 2019 Hungarian GP when the two would fight once again over the same piece of race-track.
Ahead of the season-opening Bahrain Grand Prix, RacingNews365.com journalists Dieter Rencken and Michael Butterworth analyse where each of the F1 teams stands after pre-season testing.