Unsworth, who took over following the sacking of Ronald Koeman, is hopeful of getting the job on a permanent basis but the 44-year-old knows Everton have to start winning as soon as possible.
"We need a win. We need a win for the players desperately to give them some confidence and we all need to come together and be together and win a game of football," Unsworth told a news conference on Friday.
"Sunday is a massive game for the club. It's a great game it's a great opportunity to get back to winning ways and Sunday is about Everton football club."
Lyon scored three times in the last 25 minutes on Thursday to leave Everton bottom of Group E with one point and Unsworth said he was devastated for the supporters.
"Everybody wanted to win the game for our fans... it hurts me as well because I'm one of them I am devastated for them but it's my job to pick the team up to pick a team to get everyone going again."
Everton will be without defender Cuco Martina, who fell awkwardly in the game against Lyon, while Michael Keane could return after recovering from an infection to a cut in his leg.
(Reporting by Aditi Prakash in Bengaluru, additional reporting by Shrivathsa Sridhar; Editing by Peter Rutherford and Christian Radnedge)
