Tost: Losing Verstappen was 'a problem' for Toro Rosso

Scuderia Toro Rosso team principal Franz Tost has admitted that losing driver Max Verstappen four races into the 2016 season had caused problems that the team was only now fully recovering from.

Verstappen moved to the senior Red Bull team after the Russian Grand Prix in a direct swap with Daniil Kvyat, after the Russian driver had a poor start to the season.

“Changing drivers in the middle of the season is always a problem for a team,” Tost told Motorsport.com. “The driver is an element of motivation for all the members of the team.

“Max is a special driver and losing someone like him during the season has not been easy," he added. "[He] has an incredible machine control, has no problems with the speed and understands the technical aspects very well, including the tyres."

Verstappen immediately proved his worth by clinching a historic victory in his first outing at Red Bull in Spain, while by contrast Kvyat has struggled to recover his form since being moved.

Singapore was the first time since the reshuffle that Kvyat has looked back to his old self, especially during an early spell in the race where he managed to fend off Verstappen from overtaking with some robust defensive driving.

"I loved racing today and feel this passion again,", Kvyat said after the race. "I enjoyed it a lot. The racing over this past month has been a big test of my passion but I’m loving it again so that’s mega. I pushed to the very last centimetre and left myself on the track."

Tost agreed that SIngapore had showed Kvyat was finally over the shock of losing his Red Bull seat and that the Russian was on the comeback trail at last.

"At the moment the situation is getting better," Tost insisted. "It was difficult for him to move from a team like Red Bull, which is fighting for the top positions, to a team in the midfield."

It's not yet known whether Kvyat will remain with Toro Rosso in 2017 or be dropped to make way for another driver from the deep pool of talent in the Red Bull Juniors program.

"Daniil Kvyat is a very talented driver," said Tost, who has previously suggested he would like to retain him for another season.

From the cockpit: Felipe Nasr on lights and shadows in Singapore

TECHNICAL ANALYSIS: Nicolas Carpentiers checks out the latest innovations seen in Singapore

2016 Singapore Grand Prix - Driver ratings

Keep up to date with all the F1 news via Facebook and Twitter