MILAN, April 19 (Reuters) - AS Roma's title hopes suffered a double blow on Saturday when they were held 1-1 at home by Livorno and lost Francesco Totti to a serious knee injury. Alessandro Diamanti snatched a useful point for relegation-threatened Livorno with a late free kick after striker Mirko Vucinic had headed Roma in front. In Saturday's other Serie A game, Fiorentina beat visitors Palermo 1-0 to move seven points clear of fifth-placed AC Milan and tighten their grip on the final Champions League qualifying spot. Leaders Inter Milan can extend their lead over second-placed Roma to six points if they win at Torino in Sunday's late game (1830 GMT). Four games will then remain in the title race, with Inter playing rivals AC Milan in two weeks's time. Roma look set to be without injury-prone striker Totti for all of the run-in after the 31-year-old was substituted with a ligament injury in his right knee. The club's medical staff are assessing whether Totti needs an operation, which media reports said could rule him out for up to five months. However, Roma coach Luciano Spalletti did not blame the loss of his captain for the draw. 'We lack certain qualities. Sometimes we are able to find that bit extra, other times no. We have to be a bit nastier,' he told Sky television. 'Inter have all the match points. We've wasted an opportunity.' Roma failed to create many clear-cut chances but broke the deadlock after 54 minutes when Montenegro's Vucinic netted a looping header after David Pizarro's clever chip into the area. Livorno barely threatened but shocked the hosts seven minutes from time when substitute Diamanti curled the ball into the near corner of the net. Livorno's Italy reserve goalkeeper Marco Amelia then saved twice from Daniele De Rossi, who was in tears at the final whistle as Roma, subject of a possible takeover bid, saw their chances of a first scudetto since 2001 become more remote. Livorno remain in the relegation zone but are just a point behind fourth bottom Parma, who host Napoli on Sunday. Fiorentina midfielder Marco Donadel grabbed the only goal with a 25-metre shot after 29 minutes to give them a boost ahead of Thursday's UEFA Cup semi-final, first leg at Rangers. Inconsistent Palermo had Leandro Rinaudo sent off for a second booking midway through the second half but almost salvaged a draw when Mark Bresciano hit the post. Milan's hopes of playing in the Champions League next season are fast diminishing but last season's winners will hope to stay on Fiore's tail with a win at home to lowly Reggina on Sunday.