Sparta had an abysmal period in late november/early december. After that they finally got some decent results (won at Olomouc and at Craiova). But it's not like that those wins would be after somehow great performances. It wasnt. So I dont think Sparta should be such an automatic favorite here.
They will also play on thursday one more match in conference league so probable rotation here.
Liberec decent lately, even last week where they only rescued draw at Dukla they were better side. I think they defiitely have a chance here.