The smile is back on seven-time world champion Lewis Hamilton's face as Barcelona upgrades appear to pay-off for Mercedes.

"Front Wing endplate, Floor, Rear Brake Winglets," read the official release from the FIA in terms of Mercedes updates for the Spanish Grand Prix weekend, but for Lewis Hamilton it meant the difference between battling in the midfield or chasing that elusive eighth title.

Though nobody is saying that the updates have solved the W13's issues, the car appeared far more stable in practice allowing Hamilton and teammate George Russell to out-pace the Red Bulls.

"Positive, super happy with the progress," beamed Hamilton at the end of the second session in which he finished just 0.204s off Charles Leclerc's pace, "so a big, big, big thank you to everyone back at the factory for not giving up and for continuing to push.

"We're not the quickest yet, but we're on our way," he continued. "This is the first time that we've driven down the straight without bouncing.

"We still have some bouncing," he admitted, "but it's way better and we're starting to eke out a bit of the potential in the car.

"It's still tough out there with the car," he added, "but it's much nicer than it's been before. So yeah, really grateful for those upgrades, we now need to just fine-tune them into the next session tonight.

"There's lots of data to go over to try and position the car, I think we can get it into a better place for tomorrow so that we can tackle the heels of the guys up ahead."

However, teammate Russell wasn't quite as convinced at the effectiveness of the upgrades.

"I don't know, to be honest," he said. "In Miami we were quickest on Friday and obviously here we are second, so let's see.

"The car is definitely acting differently," he added. "We've got different limitations this time. We definitely don't have the porpoising in the straights, which is good, but we are still experiencing a bit here and there in the corners, which ultimately you need to dial out in the corners, and I think the Red Bulls still look very, very strong. They look the team to be reckoned with at the moment and yes, we need to go through the data."

Check out our Saturday gallery from Barcelona, here.