In a hotly-contested race to finish second, Roma reclaimed the inside track with two games remaining after coming from behind to beat Udinese 2-1 on Sunday.
The win lifted Roma one point clear of third-place Lazio, who had leapfrogged their derby rivals into second after a 1-0 victory at Sampdoria on Saturday.
“We are halfway there,” Roma coach Rudi Garcia said on his club’s official website. “Against Lazio we can seal automatic qualification for the Champions League.
“We can win or draw against the Biancoceleste but we are not going to play for a point.
“It’s a derby and we want to win it.”
The top two teams in Serie A qualify directly for Europe’s elite club competition while the side that finishes third will have to go through Champions League qualifying.
“We need to focus on our game at Lazio,” Garcia said. “My players showed against Udinese that they can deliver when they are up against it.
“We had cool heads, played as a team and kept a high tempo.
“All great teams need those qualities.”
Lazio, who will act as hosts in the derby, have requested to the Italian Football League (Lega Serie A) to move the game from Sunday afternoon to Monday, May 25, in order to have an extra day to prepare for the match.
The Biancoceleste take on Juventus in the Coppa Italia final on Wednesday in Rome’s Stadio Olimpico.
The Italian Cup final was originally scheduled to be played on June 7 but was moved forward as a result of Juve reaching the Champions League final.