He said earlier in the day he was happy Ferrari rejigged its run plan to give him a full day in the vehicle, after cooling checks and a crash for teammate Sebastian Vettel cost him valuable mileage on the opening two days of the second test. Ferrari, who dominated the first days of testing last week, ended with the fewest laps of all teams on Wednesday (Thursday NZT).
However, during the closing stages of the afternoon session, the Scuderia pulled up just before Turn Nine, with some smoke coming from the rear before being taken back to the pits on the recovery truck.
The lap was close to the 2018 Spanish Grand Prix pole time of 1:16.173 set by Lewis Hamilton for Mercedes, and came as a boost for Ferrari after Sebastian Vettel had crashed on Wednesday. Gasly lost control of his Red Bull early on turn in at Turn 9 - the high-speed right hander - and swapped ends, going backwards over the gravel and into the barrier. "It was a pretty big crash, one of the biggest crashes I have had so far", Gasly - who posted the day's fourth fastest time prior to his accident - told reporters.
Red Bull later put out a statement on the team's official Twitter account confirming Gasly was not hurt.
Another red flag came out when Lance Stroll's Racing Point vehicle stopped in a straight.
"I still have to learn", he added, "I get more comfortable with the vehicle lap after lap and with the auto itself, so it's looking good for now".
It also curtailed the Italian team's running, with only one more lap completed in the afternoon, and forced a change of plan for the final two days.
Toro Rosso's Albon was second on the leaderboard at 1min 16.882, while British teenager Lando Norris was third for McLaren.
As for Mercedes, Hamilton managed 83 laps while team-mate Valtteri Bottas completed 96.
"After thorough checks we found that Seb's off yesterday was due to a rim issue", a Ferrari spokeswoman said.
The Frenchman, who has moved up from Toro Rosso to replace departed Australian Daniel Ricciardo, was unhurt but the impact did considerable damage to the vehicle and ended the team's programme for the day.
"It's been an encouraging start to the season and I feel about ready - I can't wait to take part in my first real Grand Prix with Ferrari".