In a delayed, eventful race of attrition, Lance charged up the order to equal the team's best finish of the year, while Sebastian similarly showcased his wet-weather skills throughout the race.
Due to a torrential thunderous downpour shortly before the original start time, the race was delayed by more than an hour.
Once it got going, it was in drying conditions, but it took a long time for the crossover point to slick tyres to arrive.
On a day where many other drivers ended up in the barriers, Lance and Sebastian kept it out of trouble on the treacherous surface to deliver 12 valuable points for the team.
Lance started the race in 11th position after Mercedes' George Russell was withdrawn from the grid, and made moves early on in the race to be in the points-paying positions by the end of the first lap.
He lost a position to the faster Red Bull of Max Verstappen before an early Safety Car was called.
Lance held position behind AlphaTauri's Yuki Tsunoda while holding off the McLaren of Daniel Ricciardo, before he gained two spots - one through Tsunoda making an error and another through Fernando Alonso retiring.
In between Virtual Safety Car deployments for cars behind, Lance started to make progress on the car ahead - which was now Sebastian.
Double points finish in Singapore
The team delivered its best result of the season under the lights at Singapore, as both Lance and Sebastian finished inside the top eight in very tricky track conditions at Marina Bay.
On lap 35, Lance made his one and only stop - for new Medium tyres - once it became clear that the track was ready for slicks.
Because of how long it took to get temperature into the tyres, combined with a great in-lap from Lance, he was able to jump Sebastian, as well as Pierre Gasly's AlphaTauri and Mercedes' Lewis Hamilton.
However, he was in turn jumped by Ricciardo, who was able to get a cheap pitstop after a Safety Car was called for Tsunoda crashing out.
Restarting in seventh position, Lance held his own and gained a position when Verstappen made an error.
This left him in sixth, and he was able to pull a small gap to Sebastian behind, and had enough of an advantage to be clear to secure sixth place at the chequered flag to take his best finish of 2022.
We have moved up in the teams' championship, which is important and a nice boost as we enter the final part of the season.
"It feels so good to pick up sixth place tonight, which is my best result of the season.
"It was also a good day for Seb, so we have come away with a big bunch of points. That is great for everybody in the team who is working so hard.
"It was a tricky race: the track surface was very slippery for the whole race, and it was not easy to stay out of trouble. It took a very long time to dry, just as it did yesterday.
"It was just a case of waiting for the areas with the new asphalt to dry out before the switch to slicks, which we timed really well.
"We have moved up in the teams' championship, which is important and a nice boost as we enter the final part of the season."
Sebastian started the race from 13th after Russell started from the pitlane, and produced an excellent opening lap to be in the top eight straight away.
In the early stages, he was closing in on Gasly while also holding off the faster Verstappen before the Safety Car was called.
He lost a position to Verstappen on the restart, and spent much of the next phase of the race in between the AlphaTauri pair.
The gaps fluctuated between the various Virtual Safety Car interventions (with Sebastian gaining one position due to Alonso's retirement in that section of the race).
Gasly pitted on lap 33, but Sebastian waited for one lap later and was able to get out ahead of the AlphaTauri, as well as Hamilton's Mercedes.
However, he lost a position to Lance and to Ricciardo - the latter gaining several positions due to the timing of a safety car benefitting him. This left him in eighth position.
I had a very strong start to the race and the first lap was great fun. I was not very patient and I pushed really hard, and gained a few places.
On the restart, Sebastian this time gained a position on Verstappen, and spent much of the rest of the race defending from Hamilton.
His defence on the Mercedes was successful, but Verstappen recovered after a late pitstop and was able to get by on the final lap as the two-hour time limit elapsed.
Sebastian finished the race in eighth position, contributing to the team's best overall result of the year.
"I think we can be happy with a strong result for the team and scoring important points. It was not easy with some very difficult track conditions.
"The asphalt took a long time to dry and timing the switch to dry tyres was critical. Maybe we went a lap too early, but overall I am happy with the result.
"I had a very strong start to the race and the first lap was great fun. I was not very patient and I pushed really hard, and gained a few places.
"After that, I concentrated on looking after my Intermediate tyres because we knew that the track would take a long time to dry and they needed to last.
"I had a big battle with Lewis [Hamilton] and Max [Verstappen] in the closing laps. I was defending for many laps and it was a shame that Max got ahead of us on the final lap."
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