Both teams had already qualified for the Champions League knockout rounds, but the Blues will now finish on top of Group E.
Giroud scored early in each half with two delightful finishes after assists from Kai Havertz and Matteo Kovacic.
The 34-year-old, who continues to be linked with an exit from Stamford Bridge, then completed the perfect hat-trick by scoring a neat-post header from N’Golo Kante‘s cross.
Giroud was then fouled in the box, giving him the chance to complete his quadruple from 12-yards out.
The Blues host Leeds United at home on Saturday before facing Krasnodar next week.
Giroud makes his point – again
Giroud had made only one previous start for Chelsea this season, in the EFL Cup defeat by Tottenham, but this haul came after he scored a stoppage-time winner as a substitute against Rennes last week.
His path to regular Premier League football is blocked by Timo Werner and Tammy Abraham, but he could do no more to take the opportunity presented to him in southern Spain.
“He’s the ultimate professional,” said Lampard. “You see his numbers for France and his numbers in the Champions League.
“He wasn’t a regular before I got here but as soon as I came in I saw his positivity, how he wants to train, how he wants to affect people, whether he starts or not.
“He’s a great example for the younger players and other players, that when they’re not always playing, they keep training well then come in and perform like he did tonight.”
The former Arsenal man put in a complete performance, not only displaying clinical finishing, but also a physical presence that tortured the home defence.
Chelsea found regular joy with runs from midfield and it was Havertz’s early burst that ended in a lay-off to Giroud, who cut back and tucked inside the far post with his left foot.
The second goal was a joy, a dinked right-footed finish over Pastor, while the header from N’Golo Kante’s cross from the right completed a ‘perfect’ hat-trick.
The spot-kick, drilled in with his left foot, was Giroud’s final act before he was withdrawn.
“I didn’t know until two years ago that you called it a ‘perfect’ hat-trick,” Giroud told BT Sport. “When I scored against Kyiv in the Europa League I said ‘what do you mean?’ It was good, I had good assists, though.
“I will try to carry on like that to finish the good work of the team. It’s always nice to be in the club history and we play football to mark our history so I’m pleased to help the team to win and to score the four goals.”
Chelsea coast to top spot
While both teams made changes safe in the knowledge their progress was already certain, there was still the carrot of a theoretically easier draw in the last 16 to play for.
Chelsea would not have expected such a straightforward evening against a Sevilla side who sit fifth in La Liga and took a point from a goalless draw at Stamford Bridge in October.
Yet, bar a period in the first half when set-pieces from the left caused trouble in the visiting defence, the Blues coasted to a fourth successive Champions League victory for the first time since they lifted the trophy in 2012.
Havertz and Pulisic, who have seen Hakim Ziyech emerge during their time on the sidelines, were both lively, while Callum Hudson-Odoi was a threat down the right.
Antonio Rudiger saw a header from a corner cleared off the line at the end of an even first period, before Chelsea dominated the second half as the hosts tired.
By the end, they had extended their unbeaten run in all competitions to 15 games, during which time they have kept eight clean sheets.
Olivier’s army – the stats
- Sevilla were unbeaten in 14 home matches in all European competitions coming into this game (W12 D2), with this their first such defeat since April 2018 vs Bayern Munich.
- Chelsea have won two Champions League games by at least four goals under Frank Lampard – only under Jose Mourinho do they have more such wins (six).
- In what was Sevilla’s 100th home match in European competition, they lost by a four-goal margin on home soil for the very first time.
- Chelsea’s Olivier Giroud (34 years and 63 days) became the oldest player to score a hat-trick in the Champions League/European Cup since Ferenc Puskas for Real Madrid vs Feyenoord in September 1965 (38 years and 173 days).
- Giroud became just the second player to a score a Champions League hat-trick for two English sides (Arsenal & Chelsea), after Michael Owen (Liverpool & Manchester United).
- He also became the first Chelsea player to score four goals in a single game since current manager Frank Lampard did so against Aston Villa in March 2010.