As expected, as we approach the half-way point in pre-season testing, this morning has seen the teams slowly begin to turn the wick up.
As they look ahead to week two and Melbourne, so we see the first updates being introduced and the first switch to the softer compounds as the focus shifts from reliability to pace.
Consequently, as the pressure increases so too do the chances of failure, and while yesterday's red flag was the result of Kimi Raikkonen intentionally running out of fuel, this morning's two stoppages were both down to technical issues.
It was all going well for Sebastian Vettel, the German having completed 40 laps in the opening eighty minutes, when he slowed to a halt at Turn 12. While on-board footage revealed a total loss of power, the Italian team subsequently admitted to an engine issue.
While the engine will be shipped back to Maranello for investigation, the required engine change meant there was no more running for the German who will be hoping to be back on track later this afternoon.
Around an hour before the lunch break the session was stopped again, this time courtesy of Nicholas Latifi whose Williams ground to a halt on the main straight not far from the end of the pitlane. "The engine died," the Canadian helpfully advised his team.
Max Verstappen almost came to grief after running over the infamous sausage kerb at T9 which meant he subsequently lost around an hour of track time.
McLaren was one of several teams trying new parts, the Woking outfit carrying out back-to-back tests with a couple of front wings.
Today finally saw drivers switch to the softest tyres in the range, and consequently it is no surprise that Valtteri Bottas topped the times on the C5 while the next three quickest drivers were on C4s.
While Max Verstappen completed the most laps (86), Renault will have breathed a sigh of relief as Esteban Ocon was able to complete 76. Though there remains a question mark over the French team's pace, it is vital that reliability is assured first.
This afternoon a number of drivers will be carrying out race simulations as the teams make the most of every available minute that is available to them this year following the decision to reduce pre-season testing track time by 25%.
Ferrari, on the other hand, has work to do.