Carlos Sainz believes McLaren has produced immediate breakthroughs with its 2019 Formula 1 challenger by learning from the mistakes suffered with last year’s car.

12 months ago McLaren had hoped for a bright start with new power unit partners Renault after a torrid three years with Honda, but as the season progressed it became clear its 2018 F1 car had key weaknesses which the team struggled to address during the campaign.

Sainz, who replaces the outgoing Fernando Alonso at the Woking-based squad, had the opportunity to drive the MCL33 at the post-season Abu Dhabi test and despite his limited experience in both last year’s car and this year’s MCL34 on the opening day of pre-season testing he’s confident McLaren has made clear gains over the winter.

“We’ve done a lot of work in the simulator over the winter that helped prepare for this test to hit the ground running, with the setup, so we didn’t need to do any adjustments” Sainz said.

“I think we have identified the big balance issues and things we need to improve. Now we need to debrief and have a clear direction that we need for the next three days to hopefully improve the car from today until the last day of testing as there is still a good margin.”

Sainz, who ended the first day of testing with 119 laps completed and the second fastest time of 1m 18.558s, suffered one hiccup when he was forced to stop at the pit lane exit after a practice start. The Spanish driver played down the issue as he focuses on adapting to McLaren having joined from Renault this year.

“There has been a lot of work put in over the winter but it doesn’t matter as the first 10 or 20 laps there are things you need to relearn, the body needs to adapt to the car, you need to find the limit,” he said.

“Once you find the limit you start feeling the nice feeling Formula 1 gives you.

“To be out on track at 9AM and as the morning was going by, not having any issues with the car at all to complete almost 120 laps is definitely a good place to start the year. The factory, the 600 people back at Woking that I’ve been together with this winter, I am sure back in Woking they will be happy at running reliably.”