Sebastian will line up ninth on the grid for the Sao Paulo Grand Prix after gaining several places in Saturday's Sprint race.
The team added 87 laps to its weekend tally in Free Practice Two, before both Sebastian and Lance raced hard in the Sprint race.
Sebastian will start in the top 10 and in a good position to score points in Sunday's Grand Prix, but Lance will start from P16 as he struggled with the car in the second half of the Sprint.
Sebastian
Sebastian started his day of running with a productive FP2 session, completing 44 laps and putting in a best time of 1.16.400 while running all three tyre compounds throughout.
With Soft tyres for the Sprint, Sebastian started from 13th on the grid and initially found himself in battles with Lance and Daniel Ricciardo.
He got by Ricciardo within a few laps, and then by Lance before passing Esteban Ocon soon after.
Sebastian then closed up the two-second gap to Pierre Gasly for ninth, before getting by with a few laps to go.
The gap to polesitter Kevin Magnussen was three seconds, and Sebastian had closed the gap to 1.5 second by the end of the Sprint.
He finished just outside of the points-paying positions, but is in a good grid position for Sunday's Grand Prix.
"I was fighting hard out there today – a few of us were stuck behind Esteban, who I think had some damage, so that lost us some time.
"Without that, I might have been able to catch Kevin before the end – and that would have earned us a point.
"Overall, however, I think we can be happy with today: our pace was good, we looked after the tyres well and we were making up places.
"Everything worked well today – let us see what we can do tomorrow."
Lance
Lance completed 43 laps during FP2, and put in a best time of 1.16.243. He sampled all three tyre compounds during the session, and completed plenty of laps on each.
For the Sprint, Lance started on the Soft tyres and had a storming start, gaining three positions on the opening lap.
Fired up for Sprint in Sao Paulo after mixed-up qualifying
Sebastian and Lance will start Saturday's Sprint race from outside of the top 10 after a topsy-turvy damp qualifying session.
He then worked his way past Gasly, and then started to close the gap to Ocon in front.
However, as the race continued Lance was less comfortable with the car and started to drop back down the order, losing positions to Sebastian and then Ricciardo.
Lance held on to 12th on the road after defending from Mick Schumacher, but a 10-second time penalty meant he dropped down the order to 17th.
He will start 16th for the Grand Prix after a post-race time penalty for Fernando Alonso.
"I made a good start and gained a few positions on the first lap.
"Everything was looking positive, but then I started to lose a little bit of pace as the race unfolded – and that meant I dropped a couple of places battling in the midfield.
"We need to look at what happened there. We go again tomorrow – and anything can happen at this place."
Mike Krack, Team Principal
"I think the Sprint served up a very entertaining spectacle for the fans today. Even though today's race is only to determine the grid, we saw hard racing up and down the grid, not least among our cars.
"Sebastian had good pace and was able to make it count as he secured ninth place at the flag.
"Lance had a strong opening lap, making up three places, but he was not as comfortable in the car today and his pace dropped off in the second half of the race.
"Nonetheless, it is Sunday that counts and we will take the lessons learned today to try and maximise tomorrow and score some points."
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