The Portuguese side were 2-1 winners in the first leg at Estadio Jose Alvalade last week but must defend that slender advantage against a Metalist side who with 26 goals are the top scorers in this season's competition.
Sporting were on course to take charge of the quarter-final tie when Marat Izmailov and Emiliano Insua put them 2-0 up last week, but Cleiton Xavier's 90th-minute spot-kick has given the Ukrainian outfit a realistic chance of progressing ahead of Thursday's return at Metalist Stadium.
Nevertheless, Lopes has backed Sporting coach Ricardo Sa Pinto and his players to get the job done.
"We will try and get the win," Lopes told reporters. "If I wasn't confident then I wouldn't go.
"We are going out there to dignify Portugal's and Sporting's names.
"We believe that we will get a good result."
Sporting head into the match on the back of three straight wins in all competitions, although their run of just one win in their last away games in Europe will be of concern.
Striker Diego Rubio believes Sporting will have to go on the attack in pursuit of an away goal to neutralise Xavier's strike for Metalist last week.
"We won an important game against a tough team that has some quality players, but we will approach the second leg as we did the first," Rubio said.
"We have to believe in the team and try to score in the Ukraine. We can't start thinking about the final already and we have to focus on one game at a time."
Metalist are looking to emulate Shakhtar Donetsk's 2009 UEFA Cup triumph and in doing so become only the second Ukrainian side to win a major European tournament.
The winners of Thursday's match face the victors of the encounter between Schalke and Athletic Bilbao. Athletic are the favourites to progress from that tie after winning 4-2 in last week's first leg in Germany.