Pirelli's 2018 tyre development progamme had Ferrari testing for the Italian manufacturer at the Circuit de Catalunya in Barcelona at the end of this week.
Initially, Scuderia reserve driver Antonio Giovinazzi was to handle driving duties on his own, but a technical problem with the team's SF70H severely limited running on Thursday.
Ferrari subsequently decided to extend its running on Friday and undertake a whopping 1,200km programme, adding Charles Leclerc to its driving force in order to give Giovinazzi a bit of respite.
Needless to say, Ferrari engineers will have been very interested in comparing the performance and technical feedback of the two young chargers relative to each other and in similar running conditions.
Extending Kimi Raikkonen's contract for 2018 appears to be a mere formality for the Scuderia, but the Italian outfit will need to decide which of its juniors - Giovinazzi or Leclerc - will likely join Sauber next season, Ferrari's de facto junior team.
Was yesterday's test a shootout between the two hopefuls? In hindsight it may well have been...