Leclerc topped the time charts in both hour-long sessions. George Russell and Lewis Hamilton were next in their Mercedes, which have struggled to keep up with Ferrari and Red Bull this season. They were within 0.2 seconds of Leclerc.

Carlos Sainz clocked the fourth best time in his Ferrari, followed by defending champion Max Verstappen for Red Bull. Leclerc leads Verstappen by 19 points after five races, but Verstappen has cut the deficit after back-to-back wins in Italy and Miami.

Teams often roll out major upgrades at the Spanish GP with a handful of races already in the bag and this well-known circuit, where teams also test in winter, is perfect for gauging progress.

Ferrari is hoping that upgrades it has brought to Spain can help it match the race speed that Red Bull has enjoyed in the last two races, when Verstappen beat Leclerc. “Hopefully (the upgrade) will be a good one and enough to be in front of Red Bull again,” Leclerc said.

Verstappen said his team won't roll out any surprises but is planning to reduce the weight of the car. “Our car is a bit fat so we need to slim it down,” Verstappen said before getting behind the wheel on Friday.

It appears that focusing on the car's reliability is the top priority for Red Bull, after car failures kept Verstappen from finishing in Bahrain and Australia, where Leclerc won. “(Ferrari) are coming with a few upgrades so it will be interesting to see what that gives them at the end of the day,” Verstappen said.

“We just need to focus on our package. We want a clean weekend.” Before practice, Hamilton and Russell both said they were expecting Mercedes to make some gains this weekend, even if they may be hard pressed to fight for the race trophy that Hamilton has claimed for the past five years.

“I do believe there is the potential there to be at the front, we just can't unlock it right now,” Hamilton said. “I'm keeping my hopes up, pure faith and trusting the team that we'll get there.”

The best result this season for Hamilton, a 103-time race winner, is third place at the season opener in Bahrain. He is sixth in the standings with 36 points. Leclerc leads with 104. Russell has so far surprisingly outperformed the seven-time world champion in his first year with Mercedes, finishing higher than his new teammate in four of five races.

?The opening practice featured the F1 weekend debuts of two drivers in testing roles. Juri Vips filled in for Red Bull's Sergio Pérez, while Nyck de Vries drove Alex Albon's Williams. Vips finished at the bottom of the table, and Vries was two spots above.

Veteran Robert Kubica also got a turn for Alfa Romeo in place of Zhou Guanyu. It was mostly an incident-free day except for a car failure that left Valtteri Bottas out of action. He said “something's broke” as his Alfa Romeo ground to a stop in the grass. The Finn was whisked back to the paddock on the back of a scooter.

Race officials expect more than 110,000 fans to turn out for each of the event's three days after two years of racing without the public due to the pandemic. The face mask that Hamilton wore in the pre-practice news conference was one of the few seen at the track.

Spanish fans are eager to see Sainz and Fernando Alonso, the last Spaniard to win the Spanish GP back in 2013. Hot, sunny and dry conditions are forecast.

The Barcelona-Catalunya track is notorious for being tough on tires. Leclerc confirmed that when he told his team by radio that “my tires are going to pieces” near the end of practice. Qualifying is on Saturday following a third practice. The 66-lap race is on Sunday.