Livorno missed the chance to catch the league leaders after a battling goalless draw at Genoa left the promoted side sixth, level on seven points with Juventus, Fiorentina and Inter Milan who all play on Sunday when pacesetters Napoli visit AC Milan.
Fabio Liverani's Genoa moved up a place to 13th with four points after a scrappy affair with few chances although the hosts came closest to scoring in when Emanuele Calaio's point-blank header forced an incredible late save by Francesco Bardi.
"It was the right result, but it's still annoying going 2-1 down in that situation," said Rossi.
"I didn't like how we started but... in the second half we changed and our courage was awarded," added the coach, who was sent off for his wild celebrations after De Silvestri equalised.
"I ran over there because I wanted to share in the joy with the lads, I didn't mean to offend anyone."
Chievo leapt out of the bottom three up to 13th place after their win, which put them level with Udinese on four points.
Sampdoria went behind to Albin Ekdal's beautifully worked goal in the 26th minute and had to wait until the 89th minute to equalise when Manolo Gabbiadini's shot squeezed through the arms of distraught Cagliari keeper Michael Agazzi.
Daniele Conti's stunning free kick in the first minute of added time put the hosts back in front but Sampdoria defender De Silvestri netted two minutes later to salvage a point.
The result gives some breathing space to manager Rossi, who has been under extreme pressure after a poor start to the season that saw them thumped 3-0 in the Genoa derby last week.
Chievo gifted a goal to Udinese's Brazilian Maicosuel in the opening minute following a defensive mix-up but hit back with a smart 13th-minute finish by Sergio Pellissier, who raced on to Nicholas Frey's through ball and fired across Ivan Kevala.
A deflected long-range strike from Luca Rigoni in the 40th minute capped off a fine first-half display from Chievo and, although they were under pressure for much of the second period, it proved enough for them to take all three points.
There are two huge clashes on Sunday with second-placed AS Roma looking to maintain their 100 percent start by beating rivals Lazio in the Rome derby (1300 GMT) while Napoli visit Milan (1945) in a match that will test their title credentials.