Lazio coach Edy Reja has described Monday night's Serie A clash at home to Juventus as the most important game of the season for his team.
Lazio currently occupy fourth place - the final position that brings with it qualification for the UEFA Champions League next season.
Udinese are currently just one point behind, with Roma a further three back with four games left to play.
Victory would bring them one step closer to their aim but defeat would not only mean potentially losing fourth spot to Udinese, but would also allow Juve back into contention.
They are seven points behind Lazio in seventh at the moment but a victory would give them a glimmer of hope.
"It's the most important match of our season - against Juve we're playing for our Champions League destiny," said Reja.
"From now until the end of the season we have to win every game but it's clear that the game against I Bianconeri is the decisive one."
However, Lazio will be without suspended captain Stefano Mauri and his preferred understudy Giuseppe Sculli is injured.
"This time I'll be forced to make changes but playing against Juve always gives everyone extra motivation," Reja added.
"We won't want for motivation and I hope we're at our best. We can't afford to mess up from now until the end."
And Reja has urged the club's fans to get behind their team, with 50,000 expected to attend on Monday night - double the club's average attendance for the season.
"I'm delighted there's this enthusiasm around the team, the help of our fans could be decisive and we hope to reward them with the Champions League," he said.