UFW rule to block access of local computer to router management interface?

I have a computer in my local network that should be prohibited to
access the management interface of the router in the browser (192.168.100.1). All other internet access should be possible, I just want to prevent with a ufw firewall rule on that system that this computer can login to the router.

I cannot find this specific use case in the ufw documentation:

https://help.ubuntu.com/community/UFW

Could you guide me into the right direction?

I think the required rule in iptables would be

Iptables -A INPUT -s 192.168.100.1 -j DROP

Thanks!