Lewis Hamilton and Nico Rosberg have become a case study of friends turning into enemies in Formula 1. They formed a close bond in the junior categories and it predictably lasted until they became title rivals.

When Hamilton first signed for Mercedes in 2013, it was amicable enough. Red Bull’s Sebastian Vettel cruised to the world championship that year, so the stakes were relatively low.

At the start of 2014, the Silver Arrows took over as F1’s dominant team. At first, they relished the battle, as evidenced by their embrace in parc ferme after an epic tussle in Bahrain.

CATEGORYHAMROSWins3222Poles3529Podiums5550Points1,3341,195Titles21Lewis Hamilton vs Nico Rosberg at Mercedes, 2013-16

But relations soured over time, and the two drivers came together in Belgium (2014), Spain and Austria (both 2016). Hamilton won the first two championships relatively comfortably, but Rosberg hit back in 2016 before abruptly retiring from the sport.

The 2015 United States Grand Prix was the last straw for Nico Rosberg

While the title fight went down to the double points finale in 2014, Hamilton sealed the crown with three rounds to spare a year later. But the circumstances of his decisive United States Grand Prix victory were contentious.

Hamilton, starting second, bullied his way past his pole-sitting teammate at turn one. Rosberg, who took to the run-off, dropped down to fifth place.

While he managed to recover to second, he made his displeasure clear after the race. After Hamilton tossed Rosberg his podium cap, the German driver threw it right back.

Lewis Hamilton and Nico Rosberg of Mercedes battle at the 2016 US Grand PrixPhoto by Mark Thompson/Getty Images

According to Bianca Garloff, a reporter at F1-Insider, Rosberg decided at that point that he would totally commit himself to beating Hamilton. He won the next seven races either side of the winter break, setting him on course for the title.

“One race later in Mexico, Ralf [Bach, her colleague] and I sat down with him and wanted to tell him that he couldn’t stand for such things,” Garloff recalled. “But he just replied that he now realised it and that he would change.

“This constant counter-attack and attention to every detail was extremely tough for Nico mentally. He was a completely different person this year because he was solely focused on this duel with Lewis,”

Lewis Hamilton knew exactly how to give Nico Rosberg a ‘dagger to the heart’ at Mercedes

Rosberg was only 31 when he retired, but the prevailing theory was that he invested so much mental energy into beating Hamilton that he was exhausted at the end of the year. The lifestyle required simply wasn’t sustainable.

While he insists that he never plays mind games, Hamilton knew how to get Mercedes on side. He would arrange meetings with the team’s senior leadership, and it was like a ‘dagger to the heart’ when Rosberg found it.

There are some similarities between Rosberg and Lando Norris, who is going for his first title at McLaren this year. The Sky pundit has made the comparison himself.

If he beats Oscar Piastri, Norris will break Rosberg’s record for the most races at a single team before winning the championship. But he too may have to break through a psychological wall first.