* Late header floors sorry Inter
* Bianchi frustrates Napoli with last-gasp goal
* Seedorf marks first game as Milan coach with 1-0 win (Adds Milan win, details, Matri quotes)
Jan 19 (Reuters) - Inter Milan's troubles continued when they slumped to a 1-0 defeat at Genoa in soggy Serie A on Sunday and neighbours AC Milan enjoyed a respite from their problems, beating Hellas Verona 1-0 on Clarence Seedorf's debut as coach.
Rafael Benitez's exasperatingly inconsistent Napoli lost ground with leading pair Juventus and AS Roma after conceding a late goal in a 2-2 draw at lowly 10-man Bologna.
Alessandro Matri, who joined Fiorentina on loan from AC Milan on Wednesday, made an immediate impact with two goals in a 3-0 win at table-propping Catania.
Substitute Hernanes scored a last minute goal to give Lazio a 3-2 win at Udinese after they twice trailed and Parma left it even later in a 2-1 win at Chievo Verona, courtesy of a stoppage time goal by Alessandro Lucarelli.
Sassuolo, whose sensational 4-3 win over AC Milan last week brought about coach Massimiliano Allegri's sacking, were brought back down to earth by Torino who won 2-0, hurling them back into the relegation dogfight.
They are joint 16th with Chievo and Bologna.
Seedorf, with no previous coaching experience, suffered many of the same frustrations as his predecessor as Milan struggled to create chances in front of a half-full, impatient San Siro.
Robinho hit the post before Mario Balotelli finally broke the deadlock by converting a penalty with eight minutes left after a foul on Kaka to give 11th-placed Milan only their sixth league win of the season.
Napoli have 43 points from 20 games, four behind Roma and 12 adrift of Juventus who both won on Saturday. Fiorentina have 40 while Inter are joint-fifth with Hellas Verona on 32.
Luca Antonelli easily out-jumped a static Inter defender to head in from a corner with seven minutes left on another miserable afternoon for Walter Mazzarri's team who have won only one of their last eight league games.
In appalling conditions, with large puddles on the pitch, Genoa goalkeeper Mattia Perin ensured three points with a superb late save from Ruben Botta's header.
It was an especially enjoyable win for Genoa coach Gian Piero Gasperini who had a miserable spell at Inter at the start of the 2011/12 season and suffered the indignity of being sacked after five games in charge.
Napoli trailed at halftime at Bologna after Rolando Bianchi got away from his marker to score with a glancing header.
Gonzalo Higuain equalised with a penalty in the 62nd minute and Jose Callejon fired Napoli ahead with 10 minutes to go after Bologna lost possession.
The hosts had Panagiotis Kone dismissed for a second bookable offence but Napoli relaxed too soon as they left Bianchi unmarked to fire the equaliser in the 90th minute.
Matri needed only 45 minutes to better his tally of only one goal in 15 appearances for Milan.
Having set up the first goal for Matias Fernandez just before the half hour, he scored twice from close range in a 13-minute spell before the break, showing the kind of opportunism he lacked at Milan.
Matri was hired after strikers Mario Gomez and Giuseppe Rossi both suffered knee ligament injuries.
"I haven't experienced a moment like this for a while and to be honest I really needed it," Matri told reporters.
"I wanted to become a leading competitor again. I struggled to settle into Milan's tactics and there were various problems at the club." (Reporting By Brian Homewood; Editing by Justin Palmer/Rex Gowar)