An ill-timed red flag caused by Charles Leclerc’s Ferrari prevented both drivers from maximising the Soft tyre before Pierre Gasly's yellow-flag incident compromised further laps.
It meant the order at the end of Friday remained relatively mixed up ahead of qualifying tomorrow.
While the second session proved somewhat disruptive, Lance and Sebastian were able to conduct important running in first practice.
The duo worked on a similar run plan and began the hour’s session on the Medium tyre to establish a baseline for the AMR21.
Lance and Sebastian ran inside the top 10 throughout the first half of the session. Sebastian's 1.45.685 lap proved good enough for fifth early on, and Lance would complete his first run in 1.45.737 and slotted into seventh.
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The drivers would remain on the Medium tyre for the remainder of the session, which became increasingly disrupted, as incidents at Turns 4 and 15 caused yellow flags that prevented the field from easily finding improvements.
Lance would find a clear track under green flag conditions to improve to a 1.45.234 time for 13th, and Sebastian's next effort lowered his best to 1.45.415 for 15th.
Their times were completed on the Medium tyre, while the majority of the cars ahead had set their best times on Softs.
The second practice session included Hard and Soft running, as the team worked to improve its understanding of the Baku City Circuit and the three Pirelli compounds.
Despite a myriad of yellow flags, both drivers completed five laps on the Hard tyre before switching to the Softs for the first time.
They then set personal best sector times on their first flying laps before the red and yellow flag incidents that affected the field’s Soft tyre runs.
Despite worn Softs, the duo improved in the final half of the session. Lance set a 14th-best time of 1.43.812, while Sebastian lapped closely behind in 1.43.881 for 15th.
Sebastian would return to the used Hard tyre for the final minutes of the session while Lance continued to lap on the Soft, giving the team plenty of data to review ahead of qualifying.
Lance: "It is great to be driving in Baku. It is a place that holds special memories for me and it is great fun to drive here. It is so high-speed; you are constantly close to the wall, and it is a challenge for the driver.
"You can gain a lot of lap time under braking because you arrive at high speeds, and getting the braking point right really helps bring a lap together.
"I think we made some good progress with the car today; we learned a lot about the set-up and I think we can make further gains with car balance. We will go away tonight, review it all, and try to make improvements for tomorrow."
Sebastian: "We covered plenty of laps and end the day feeling satisfied that we have done our homework. The track was in good shape from the start, but obviously improved quite a bit during the day.
"It is a tricky circuit at the best of times, but by the end of the sessions I was finding a nice rhythm. During my laps on the soft tyres, I did not maximise everything and I am sure it is the same for the others because there were a lot of yellow flags, especially this afternoon. So there is more to come.
"The long runs were a bit cleaner and I have a good feel for the car already. Let’s see where we can improve overnight."
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