The Spanish veteran was among the pacesetters early on, but dropped back as the session developed and appeared to have a problem with the performance of his engine, judging by radio transmissions between the Spaniard and his engineer.
Alonso, who retired in Monaco last Sunday with an engine failure, ended his session about five minutes early as a result.
The main talking point of the weekend so far is the new front-wing flexibility test introduced by governing body the FIA, aimed at reducing the amount teams can use flexing wings to control aerodynamic performance.
Red Bull, the prime force behind persuading the FIA to introduce the test, and Ferrari have hopes that the tougher restrictions will boost their competitive hopes. McLaren believe it will have next to no effect on relative competitiveness.
Teams have long used front wing flexibility to boost speed on the straights, while retaining downforce in the corners. The idea is that the wing ‘backs off’ on the straight to reduce drag, before moving back into its maximum downforce-producing position for the corners.
But under this generation of cars the phenomenon has proved useful in tuning the cars between high and low-speed cornering performance.
The generations of cars introduced with new rules in 2022, which focus on underbody downforce produced by so-called Venturi tunnels, have proved prone to low-speed understeer – a lack of front grip – and high-speed oversteer – too much front grip.
By making the front wings become less effective at higher speeds, teams can reduce this nervousness in quick corners without making the cars too hard to drive at low speed.
McLaren and Mercedes are widely perceived to have been the pioneers of this particular approach, but it remains to be seen whether the tougher tests will have any effect.
It will be hard to tell at this track for sure, as its combination of medium and high-speed corners should relatively suit Red Bull. It is a circuit with similar characteristics to Suzuka, Jeddah and Imola, where Verstappen was competitive, compared to circuits with a lower average cornering speeds, such as Miami, Monaco and Bahrain.