A strong session from Pierre Gasly showed strong potential within the Alpine A525 and built of two smooth days of running prior.
Gasly topped the morning session on Friday for a time to mark the Enstone operation out as the biggest improver on track.
Last year, Alpine headed to pre-season with a dramatically overweight car and a bleak outlook.
Improvements throughout 2024 gradually addressed key issues and, though it has retained the same basic chassis for the coming campaign, looks a far more competitive prospect.
“We had three smooth days with no issues and the car ran well all week, which meant we could achieve plenty of laps and plenty of mileage,” Doohan said of the test.
“We collected a lot of great data and, on a personal side, I took on some useful knowledge to apply in Australia for the first race.
“Conditions have been mixed all week but that’s good to put us all through our paces.
“I am going into Melbourne with confidence. There is much more to come.”
Though Alpine impressed, team boss Oliver Oakes moved to temper expectations.
While the front four teams performed largely in keeping with expectations and looked clear of the pack, the gap to the midfield looks to have closed.
That prompted McLaren team boss Andrea Stella to suggest there is no longer a group of four teams are the front, but six.
Common wisdom in the F1 paddock is the additions are Williams and Alpine.
“Testing is never easy to fully understand where you stand in the pecking order,” Oakes warned.
“We’ve really focused on ourselves this week and I am pleased with the things we have learnt and how we have progressed across the three days.
“We have a good base to work from and a solid foundation to start the season.”
The season kicks off with the Australian Grand Prix on March 13-16.
