In first practice, Aston Martin’s Fernando Alonso rescued what could have been a high-speed crash at the harbour front chicane.

The rear flicked sideways as he went over the crest at the start of the braking point, and as he corrected, the car fishtailed, sending the front towards the barriers.

Although the incident broke the car’s front-wing endplate, Alonso kept it largely under control and out of the barriers as it slid wildly up the kerb on the outside of the circuit.

Aston Martin had a difficult time in the second session, Alonso ending up 20th fastest and team-mate Lance Stroll slowest of all, and 0.880secs off the Spanish veteran.

Alonso said: “It’s a little bit of everything. We are not happy with the front axle, losing a lot of front grip in the middle of the corners and we have this chronic understeer we cannot solve.

“Upshifts, downshifts, harvesting level into the corner in Monaco is crucial to be precise and confident into the corners and at the moment it is way too inconsistent the way the car downshifts and the speed you approach the corners. It is not easy to drive. We are not at the level yet.”

The 44-year-old also came up with the latest in a series of eye-catching lines to describe his unhappiness with the new cars introduced by this year’s rules, with their nominal 50-50 split between internal combustion and electrical power.

“This is the worst generation of cars I drove in Monaco,” he said. “The way you charge the engine with the braking and lifting off creates a lot of inconsistency into the engine braking, sometimes you have less, sometimes you have push, sometimes not.

“If the battery is full, you don’t recharge so you don’t have engine braking. It’s like pushing. It’s just the rules. Hybrid cars should not be racing. Simple as that.”