The 16-year-old Bristol Sport Racing driver took another double pole in qualifying before powering to a comfortable lights-to-flag victory in the first race and a thrilling win in the second.
And it was enough for the delighted ADD Motorsports-supported racer to take the lead in the Championship for the first time this year.
He said: “It was a near perfect weekend. I took pole with my only full lap in both qualifying sessions and drove really well to win both races.
“The first win was by eight seconds and pretty comfortable, I just had to make sure I didn’t make any mistakes.
“The second was really exciting and much closer, so it was great to come out with the points.”
Lando was fast in testing and managed to finish second fastest in the second session on old tyres while most of his competitors had changed to new.
Red flags disrupted both qualifying sessions leading to chaotic proceedings, but followed very similar paths for Lando.
Both first full laps he attempted were interrupted by a red flag, with the Somerset driver getting his best lap in on his only full lap before another red flag.
He managed to take a double pole, getting over the line in the second with a second to spare before the red flag came in play – with a lot of drivers unable to get a lap in.
Lando got off to a great start in the first race –the first wet race of the year.
The safety car was brought out on the first lap for two laps, but Lando got a good restart and soon built up a commanding lead.
He was over a second-a-lap faster than his competitors and out in front could focus on not making any mistakes, taking the win comfortably by eight seconds at the end.
Race two was a lot closer, with the team taking a different strategy than most of the other drivers, running on a lower downforce package meaning he was faster on corners but slightly slower on the straight.
He got off to a good start from pole before another safety car came out on lap one.
After the restart, Lando swapped the lead with Defourny nearly every lap in a thrilling battle.
He eventually settled into second for around three laps, saving his tyres and waiting for the right time to make his decisive move.
And with two laps to go he made a brilliant pass on the inside of La Source before breaking free and going on to the win.
Lando became the first driver to win both races on one weekend in the Championship this season with his fourth win. It was enough to put him 11 points clear at the top of the standings.
He added: “It was a great weekend, we were really fast – the team did a good job.
“I did really well in qualifying to get my laps in, just one slight mistake in the second one would have seen me drop right down.
“And to take two wins in this manner has really helped push me right up there and turned it around for me.
“It’s great to go top at this stage, but there’s a long way to go.”