ROME, Dec 14 (Reuters) - Only a win will do for Serie A contenders AS Roma and Palermo who meet in Rome on Sunday.
Roma, who are in second spot, slipped seven points behind leaders Inter Milan after losing 3-0 to Lazio last weekend.
Third-placed Palermo are a further point behind and, with Inter hosting a Messina team that has lost its last four games, a draw at the Olynpic Stadium would almost certainly leave the Milan side nine points clear at the top.
Roma's derby defeat was a huge disappointment after a run of six straight league wins but coach Luciano Spalletti believes his side are still capable of making up ground on the leaders.
'A strong team shows its true colours in the most difficult times,' he said in La Gazzetta dello Sport. 'We're still in the title race. We just need to believe in ourselves.'
At Palermo, on the other hand, some people are already starting to question whether Inter can be caught.
'I think they will win the title with a margin of between 15 and 18 points,' said club president Maurizio Zamparini before describing Roma versus Palermo as a playoff for second place.
Whatever the outcome, the contest looks evenly-balanced on paper and both clubs have full-strength teams at their disposal.
Roma captain and Serie A top scorer Francesco Totti has fully recovered from an ankle injury and will be keen to add to his tally of nine goals this season.
Palermo also have plenty of firepower. Strike partners David Di Michele and Amauri have got 13 goals together and midfielder Fabio Simplicio scored two in last week's 3-0 win over Livorno.
While the game at the Olympic Stadium could go either way, Inter should have little trouble disposing of Messina.
The champions are on a roll. Victory on Sunday would make it nine consecutive Serie A wins - a club record that would break the one that has lasted since the 1939-40 season.
At the other end of the table, Fiorentina take on AC Milan on Saturday in a match that highlights their change in fortunes.
Twelve months ago the teams were battling for the title. Following the punishments in the match-fixing scandal, however, both are hovering just above the relegation zone.
Milan's eight-point penalty is light against Fiorentina's 15-point deduction, but the six-times European champions are going through their worst run of results in recent years.
Last weekend's drab 0-0 draw with visitors Torino, in which Alberto Gilardino missed a penalty, highlighted the loss of their once razor-sharp finishing instincts.
Coach Carlo Ancelotti insists results will improve after Christmas when key players return from injury, including keeper Dida, defender Alessandro Nesta and winger Serginho.
Meanwhile, Fiore's players will try to increase Ancelotti's woes by pushing his team closer to the relegation zone.