After Walker's shot was deflected into his path on the edge of the box, Rodri fired in a ferocious first-time strike that was going in anyway but took a touch off Chelsea substitute Trevoh Chalobah on its way into the net.
Chelsea striker Giroud received the ball from Eden Hazard and jinked his way past two Southampton players in a crowded area before he stabbed the ball home.
Thehome side added a second on 53 minutes when Hwang Hee-chan picked out an easy finish for Matheus Cunha at the far post and the Brazilian then turned provider when Craig Dawson poked home a low cross.
The Brazilian then completed his hat-trick from the penalty spot after being brought down by Malo Gusto, sending Petrovic the wrong way with eight minutes remaining to put the result beyond doubt before Silva headed in a late consolation.
Makeshift left-back James Milner played a through ball into the space down the middle, which Daniel Sturridge opened up into the path of Firmino who calmly slotted home.
The Madrid coach backed Ronaldo as the "clear" front-runner for the Ballon d'Or this week despite a run of one goal in his last five league games, and he led theway in Vitoria as the pacesetters came from behind to win comfortably.
It was a childhood dream to record with the legend Femi Kuti. It's one thing to have that dream, another for it to come to pass and you actually love the record. The vibe was surreal - we were shooting in The Shrine, thehome of Afrobeat!"
Solanke doubled the advantage from the penalty spot just past the hour mark, sending Leno the wrong way for his 12th league goal of the season after Antoine Semenyo was bundled over by Joao Palhinha.
A defeat in Istanbul against Galatasaray - a team they have never beaten away from home in the Champions League - on November 29 will see United exit at the group stage.
With fit-again Michael Olise subbed on in the second half for his first appearance of the season and Eze electric, the momentum seemed to be firmly with thehome side.
The Colombian forward danced his way into the box and coolly side-footed beyond Thomas Kaminski at the near post to give the hosts some breathing space on what had initially looked like a night when they could slip up in the title race.
Having scored his first ever Premier League goal at the weekend against West Brom, he netted again in the derby to set us on theway to a hard-earned three points.
A second successive brace from Nicolas Pepe gave us all three points on the final day of the season, but results elsewhere didn't go our way, meaning we finished eighth for the second year in a row.