Then Formula Renault 3.5 driver Guerrieri won "many admirers" on his way to his only previous Top 50 appearance in 2010. You'd be forgiven for thinking he'd been in a career wilderness since - two runner-up finishes in Indy Lights failed to prolong his single-seater career - but Guerrieri has reinvented himself in tin-tops, first in his native Argentina and, more recently, on the world stage, where he has become an established frontrunner with Honda in World Touring Cars.
Guerrieri showed great adaptability when he was drafted into Honda's TC1 World Touring Car Championship line-up in late-2017 with little notice, and this season the Argentinian has channelled the emotion that cost him the odd result last year and added a level of consistency to the form that earned him third place in the 2018 WTCR points standings.
Four wins - the most impressive of which was arguably his drive from ninth in the reversed-grid race at Sepang, which ensured the WTCR title fight went to the final race and set up a spectacular, albeit ill-fated bid - marked a fine return for Guerrieri, whose Munnich Motorsport team maximised the Honda Civic Type R at its disposal and regularly beat the better-resourced BRC Hyundai and Cyan Lynk & Co squads.
Guerrieri's ability to dig deep in response to adversity shone through in 2019, and it's that willing that not only earned him a place in the Top 50 but also meant he is correct to say he has "nothing to feel to feel bad about" despite missing out on the WTCR title.
We started knowing each other since [we were racing] karts. We were not [close] friends, but we always liked each other. We kept in contact when he was in Europe, but less than we had in Argentina because each other was focusing on his [own] programme.
I remember one time when I went to Monza for my first experience in Formula Renault, he was the guy that gave me all the feedback for this weekend. He wrote an email, like three pages, with all the [information about] - ‘where I have to put the wheel, where I have to hold wider or closer, clip the apex’ - and it was exactly the same as I did.
When he had to come back to Argentina after the Indy Lights period we were closer, because we both lived in Buenos Aires. I remember sometimes when we did track walks, he was racing for Toyota, I was racing for another manufacturer, and in the track walk we met in the same part of the track, seeing the small details that no-one was seeing. We discovered each other - 'Ah, you have seen that point!'
Our dream was planned in my house, my apartment, in 2015. I remember we said, 'We have to race in Europe, live in Barcelona, race in the same team'. And we worked so hard together to get it.
I was in 10 different teams in my career, five different manufacturers with more than 20 team-mates, and never had this feeling before. Everything is clear, nothing is hidden. You can watch his camera, he will give you exactly the feedback [and] I will give him exact feedback and we work together as proper team-mates. This feeling is difficult to find. For sure, both want to beat each other, I would be lying to you if I said, 'No, I don't want to beat Esteban', because it's not true. But in the moment that we are putting everything on the table, we don't lie, we just say the truth to each other and say, 'This change I did on my car worked'. This is how you build up the speed; if you start to hide something, both are building the speed slower than in one way.
He's really emotional, he's really passionate, [but] he's a good guy. I believe in God, and I think if you are a good driver, it's not enough. You need to be a good person. As a human being, he really [would have] deserved this championship.