Does I94 supercestaydes I797?

[H1BQuery2011]

I have got my L1A Individual valid until Nov 2019 and I have valid stamped visa on my passport until 2021.

In my recent entry to US, I got the I94 until 2021 (my visa expiry).

Given the above situation, below is my question:
(1) Can I stay until 2021 now as I have got the valid I-94 until 2021?
(2) Do I have to extend my L1A petition still ?

[Libra_14]

(1) Can I stay until 2021 now as I have got the valid I-94 until 2021?

Yes, you can stay till 2021 (I94 date) - but cannot work beyond your I797 date.

(2) Do I have to extend my L1A petition still ?

Yes, you'll have to extend your petition in order to work.