Olivier Giroud's fantastic four goals put the Blues on an unassailable 13 points at the top of the group, with tonight's opponents Sevilla settling for second.
However the 34-year-old shone brightest on the night, as he proved unplayable for the Blues on a flawless evening in Spain.
Giroud genius gives Lampard headache
Giroud's performance tonight bordered on perfection for Chelsea, as he grabbed his opportunity with both hands at the Ramon Sanchez-Pizjuan Stadium.
Even looking past the quality of the goals; a remarkable perfect hat-trick and an emphatic penalty, the French international worked tirelessly as he gave his manager the ultimate selection conundrum.
The look on the manager's face as Giroud made it three was enough to see how much delight the Frenchman's fine performance will make the entire squad. However, the boss may not be as happy at the upcoming 72 hour headache.
Havertz shows what he can add
It's fair to say Kai Havertz has struggled the most with the transition of joining Chelsea for the 2020/21 season.
A mix of games out of position as well as COVID have limited the German's influence on his new side, however the new 'Number 8' roles which have opened up in Lampard's side have created a new opportunity for him to make his mark.
Mason Mount's brilliance this season makes him the number one option in that position, however the battle between Mateo Kovacic and Havertz for the other role is an intriguing one.
Both started today, with both picking up classy assists before being replaced with 23 minutes to go, stating their cases for the chance to start against Leeds.
In his first start since catching COVID, Havertz did himself no harm with his performance.
Back-up defenders keep first team on their toes
Lampard had the luxury tonight to be able to rotate his entire back four, giving Cesar Azpilicueta, Antonio Rudiger, Andreas Christensen and Emerson an opportunity.
So much has been made of how impressive Chelsea's starting defenders have been since emerging as the number one choices, so this game was important for those playing to remind everyone of their quality.
All four never looked in trouble at the back, with Rudiger particularly showing commanding defensive skills.
Emerson was a threat throughout going forward down the left, with Azpilicueta and Christensen putting the team at ease.
While the boss may not be looking to change the back four just yet, it was important for the reserves to perform when they got the chance.