Mercedes had set a record for the most dominant start to a Formula 1 season, with four consecutive one-twos, in the previous race in Baku and Ferrari were floundering.
At different stages of the Barcelona race, both Leclerc and Vettel were given team orders to benefit the other. In the end, neither red car was on the podium and the Silver Arrows had another one-two.
Italian GP: Leclerc plays the quali game
Vettel towed Leclerc onto provisional pole at Monza, perhaps happily safe in the knowledge that Leclerc was due to return the favour in the second set of runs in Q3.
However, the desperate search for a slipstream led to farcical circumstances and Leclerc perhaps cheekily took advantage, doing little to clear up the chaos, failing to give Vettel a tow and, in the process, securing pole for himself.
Singapore GP: Ferrari undercut Charles with Seb
Having won from pole in Belgium and Italy, Leclerc was on a roll with a third qualifying win in succession arriving in Singapore thanks to Ferrari's aerodynamic upgrade.
Ferrari's strategy hasn't always been at its sharpest, but Vettel was sprung from P3 to the lead of the race by a perfectly timed undercut. The only issue – it was at the cost of his team-mate, who was left thoroughly unimpressed as Vettel was allowed to keep the win by the team.
Russian GP: Vettel's payback, before race falls apart
Much like the pre-arranged plan for Monza qualifying, Ferrari once again plotted after Leclerc took pole in Russia, with Vettel in third behind Lewis Hamilton.
Leclerc would tow Vettel past the Mercedes, and possibly into the lead, but Vettel would give the place back, right? Wrong. Vettel bolted clear, prompting messages back and forth between the team and both drivers.
Ferrari seemed to have taken matters into their own hands, leaving Vettel out on worn tyres, before pitting him once Leclerc had closed the pit window – only for disaster to strike, Vettel suffering engine failure, and Mercedes jumping Leclerc under the consequent safety car.
Brazilian GP: The crash
With scrutiny now coming on Ferrari over the legality of their power unit, Vettel and Leclerc had put up a united front in defending the team's practices.
However, Interlagos saw them sink to new lows, Vettel and Leclerc touching on the back straight, eliminating both from the race and prompting Binotto to summon both to Maranello to explain themselves.
GPFans is a multi-platform, multi-language brand dedicated to Formula One coverage. We bring you all the ins and outs of the sport, 24/7, everything from up-to-the-minute news and features to the latest viral stories and clips.
We believe that a new generation of exciting, outspoken drivers will make F1 more popular than ever before, and we want to give our users access to as much of their heroes as possible, on and off the track. From Lewis Hamilton to Max Verstappen, Daniel Ricciardo to Sebastian Vettel, we provide in-depth analysis of every every Grand Prix in the season, from Australia to Abu Dhabi.
With Formula One under the new ownership of Liberty Media, how the sport is being covered is evolving, and GPFans will look to be at the heart of this progression into new media, as one of the fastest-growing sites covering the king of motorsports.