Roma already erased a three-goal deficit once in this season's Champions League.
The Giallorossi believe they can do it again against Liverpool on Wednesday.
"We've already shown we're capable of coming back and we should have the belief that we can do it again," Roma coach Eusebio Di Francesco said.
Liverpool won the first leg 5-2, so Roma needs a repeat of its 3-0 second-leg victory over Barcelona in the quarterfinals to reach next month's final in Kiev.
A 4-1 win — Roma's result against Chievo Verona on Saturday — would also suffice.
"I believe. That's my slogan and that's what I want to transmit to my players," Di Francesco added.
However, Roma will have to find a way to stop its former striker, Mohamed Salah, who scored the opening two goals of the first leg.
Security will also be a concern following clashes at the first leg that left a Liverpool fan in critical condition.
Italian state police said "special attention" will be paid to the arrival and movements of 5,000 Liverpool supporters in the capital.
Wednesday's game is a rematch of the 1984 European Cup final that Liverpool won in a penalty shootout in Roma's stadium.
In the other semifinal, Real Madrid will look to protect a 2-1 lead against Bayern Munich on Tuesday as it seeks a third consecutive title.
REDS REUNITE
Liverpool should have its devastating front three intact for the second leg, with coach Juergen Klopp saying Sadio Mane will be fit after a minor thigh injury.
Mane, who missed the 0-0 draw with Stoke in the Premier League on Saturday, will link up again with Salah and Roberto Firmino — reuniting the players who scored all of Liverpool's goals in the first leg. They have scored 28 goals between them in this season's Champions League, more than any other team in the competition.
Klopp does have issues in midfield, though, with Alex Oxlade-Chamberlain out for the rest of the season after sustaining a serious knee problem in the first leg to join fellow midfielders Adam Lallana and Emre Can on the injury list. Jordan Henderson, James Milner and Georginio Wijnaldum are Klopp's only fit senior midfielders.
Liverpool, a five-time European champion, has proved to be the master of the counterattack domestically and in the Champions League this season, so is the last team that Roma will want to be gung-ho against. The Reds did, though, squander a three-goal cushion against Sevilla in the group stage to draw 3-3.
Roma's tactics for stopping Salah: Never lose sight of him
Liverpool striker Mohamed Salah moves so fast that it's difficult to keep an eye on him.
Yet that's exactly the advice Roma coach Eusebio Di Francesco has given his players before they face their former teammate in the second leg of the Champions League semifinals.
Salah scored two goals in the first half of the opening leg, setting Liverpool on its way to a 5-2 victory.
Roma needs to win by a three-goal margin on Wednesday to advance to next month's final in Kiev, Ukraine, so Di Francesco is putting the emphasis on attacking while instructing his squad to be more aware of Salah's darting movements.
"We can't move a chunk of the squad around just for one player — even if he was decisive in the first leg — or try to put the entire squad's focus on Salah," Di Francesco said Tuesday. "All I can say is this player is unbelievably skilled when he moves vertically and we need to be a bit better at reading certain situations.
"It's not like we can put three players on Salah. That's out of the question, because we need to spread our energies around," the first-year Roma coach added. "Yes we need to account for the opponent but we need to focus on ourselves and doing something great to erase the three-goal deficit."
Salah has scored 43 goals in 48 appearances in all competitions this season.
"If you lose focus just for a second in games like this, you get punished," said Roma midfielder Radja Nainggolan, who has never scored in 23 Champions League appearances. "We need to be fully focused for 95 minutes and give everything - that's the only way we'll be able to turn this around."
Roma has not conceded a goal in their five Champions League home matches this season, and it's clear that the Giallorossi want to duplicate their surprising 3-0 win over Barcelona from the quarterfinals.
"I would do it like on a computer or telephone — copy and paste," Di Francesco said. "We want to create another miracle, if you will. But we all need to do a lot more than we did in the first leg."
Roma will be without physical midfielder Kevin Strootman, who injured his chest in the first leg.
There are concerns over fan violence surrounding the match after two men from Rome were arrested on suspicion of attempted murder following an assault outside the stadium before the first leg that left a Liverpool fan in critical condition.
"I can assure you there are really great fans in Rome — real fans — who mean well," Di Francesco said when asked about the incident by a British journalist. "But a very small part of them — and I think you have them on your side, too, and generally all around the world — can ruin a beautiful sport like ours.
"So I want to issue an appeal: I hope it's really joyful and fun to come to the stadium, beyond the result."
The game is a rematch of the 1984 European Cup final that Liverpool won over Roma in a penalty shootout at the Stadio Olimpico — and it's the first time that Roma has reached the semifinals since that year's competition.
"Too much time has passed since that final for these players to realize what it meant," said Di Francesco, who as a player helped Roma to the 2001 Serie A title. "That's more in the hearts of the fans.
"The motivation for them should lie elsewhere, playing a Champions League semifinal. We need to build belief that we can achieve things in this competition."
Schick should take pressure off of Dzeko against Liverpool
Roma waited all season to see what Patrik Schick can do.
Plenty, it turns out, as evidenced by his last two appearances in both the Champions League and Serie A.
The 22-year-old Czech Republic striker can impose his physical presence as a center forward and can also take some of the attention off of more established No. 9 Edin Dzeko when he lines up on the right wing.
Expect Roma coach Eusebio Di Francesco to select the second option for Wednesday's return leg against Liverpool in the Champions League as part of a more offensive 4-3-3 formation — with Stephan El Shaarawy on the left wing.
Roma needs to overturn a 5-2 deficit and Schick should start ahead of Cengiz Under, the Turkish winger he replaced for the second half of the first leg, when Schick inspired Roma to score twice and give the Giallorossi a glimmer of hope for reaching next month's final in Kiev, Ukraine.
"At the end (of the first leg) we saw they are not as strong in defense as they are in attack," Schick said. "We have the chance to score three times at home. We have to go out there without fear, with real fighting spirit and courage."
Schick scored the opener in a 4-1 win over Chievo Verona on Saturday.
"Schick is the proof that when you find that mental strength and confidence, you can hit great heights regardless of the tactics," Di Francesco said.
"He played in a wider role, which people had said he wasn't suited to," the coach added. "He has improved physically, because to play on the wing you've got to have a good running level and he's got that."
Having been slowed by injuries and ailments for much of the season, Schick has now scored twice in his last two Serie A matches — his first league goals with Roma. He also featured prominently in the remarkable 3-0 win over Barcelona in the second leg of the quarterfinals, showing off both his aerial skills and skilled feet.
The Chievo game marked the first time that Dzeko and Schick started together and both scored.
"The understanding with Dzeko is improving," Schick said. "We speak together in Czech — he played there 10 years ago and speaks my language very well. In the dressing room and on the pitch we speak Czech."
After emerging at Sampdoria with 11 goals last season, Schick had been set to join six-time defending champion Juventus but the deal collapsed because of a reported heart problem.
Sampdoria coach Marco Giampaolo initially used Schick as a substitute, but the youngster scored on his first start — against Juventus — and after netting in three straight matches in December it became difficult to leave him out of the starting lineup.
That scoring streak was capped by a spectacular strike against Chievo when, with his back to goal, Schick flicked the ball over a defender and raced through the opposition before driving home a precise finish.
Schick made his league debut for Sparta Prague in 2014, but his career took off during the 2015-16 season while on loan at Czech club Bohemians.
Sampdoria then signed him the following year for a fee of about 4 million euros ($4.8 million), and Roma snapped him up in August on a club record deal adding up to about 42 million euros ($51 million) — the same fee that Liverpool paid for Mohamed Salah two months earlier.
"I have been operating in the role of a sporting director for 17 years," Monchi, Roma's transfer market mastermind, said at the start of the season, "and this is perhaps the signing where I feel the most pleased, satisfied and proud."