The Blues had to come from behind at the Stade Pierre-Mauroy after Lille went ahead through Burak Yilmaz’s penalty, although we never relinquished our aggregate lead thanks to the 2-0 first-leg victory at Stamford Bridge.

We didn’t need to rely on that previous result to progress, though, as Christian Pulisic equalised with a composed finish on the brink of half-time and an improved second-half performance, after tactical changes at the break, resulted in Cesar Azpilicueta’s winning goal, making it 2-1 to Chelsea on the night and 4-1 on aggregate.

The man with a plan, or two

This was a significant game for Thomas Tuchel, both in terms of seeing his team continue to succeed in difficult circumstances on and off the pitch, as well as statistically speaking.

It was his 50th Champions League match as a manager and saw him secure the best record of anyone after that number of fixtures, with his 32nd victory in those 50 games beating Zinedine Zidane’s previous record by one. It was also his 50th win as Chelsea head coach in all competitions, in his 78th match with the club, giving him a 64 per cent win ratio, having drawn 19 and lost just nine.

He played a major hand in this victory in France too. At kick-off he opted to shift the team’s shape slightly by going for a back three and a trio in central midfield, with N’Golo Kante, Jorginho and Mateo Kovacic all starting.

That extra man resulted in the Blues denying Lille access to the centre of the pitch and controlling midfield in the first half, sometimes by any means necessary, with Kante being punished for seven fouls, the only person to commit more than three. Our equalising goal provides an example of the control we exerted at times in the opening 45 minutes, as the build-up to Pulisic's strike was a spell of possesion lasting one minute and 15 seconds, featuring 24 passes with every outfield player involved at least once.

However, with Lille themselves going for a 4-4-2 and introducing a big target man in Yilmaz since the first leg, the home side had their own plan, which involved getting the ball wide and delivering crosses into the box. That was clear from the fact they attempted 18 crosses in the game, compared to Chelsea’s eight, and that five of our 11 total blocks came from wing-backs Cesar Azpilicueta and Marcos Alonso.

The threat of those deliveries was clear as they aimed at either Yilmaz or midfielders Xeka and Benjamin Andre, who were arriving late in the box to use their height. Those two both won four aerial duels, the joint highest of any player.

Adapting to the threat

Tuchel isn’t the type of coach to sit by and let that situation continue, acting quickly to bring on Mason Mount for Kovacic at half-time and revert to a 3-4-3 formation. It wasn’t a drastic shift in approach, though, with Mount playing a similar role to Kovacic, trying to provide the attacking impetus with bursts forward on the ball and spending a lot of his time taking up wide positions on the left.

That can be seen from the similar statistics posted by Kovacic and Mount in their 45 minutes of action each. Kovacic had the joint-highest number of dribbles for Chelsea – four, along with Kante – while Mount was just behind him on three.

In fact, it seemed there as a strong desire from all our midfielders to look for opportunities to run with the ball to open up space, as even Jorginho, usually the definition of a pass-and-move footballer, registered three successful dribbles past an opponent.

However, the difference in the second half was that Mount was operating higher up the pitch, especially off the ball, as we attempted to win possession earlier and use the extra width provided in those areas by a front three to prevent Lille from building attacks down the wings from their full-backs. As a result, and despite playing just half the game, only Jorginho made more than Mount’s three tackles for the Blues.

Fine margins

This was one of those high-intensity Champions League ties when the smallest of margins suddenly became crucial to the outcome, requiring plenty of concentration from the players in addition to their physical exertions.

That made for a frustrating game for both goalkeepers, Edouard Mendy and Leo Jardim, as there was little either of them could do about any of the three goals on the night. With neither side prepared to back down, the match was short on chances, but when they did arrive the strikers were clinical. At half-time the teams had managed one shot on target each, but converted them both to make the score 1-1.

In a further sign of how well Tuchel’s changes at the break worked, that was the only shot on target Lille managed in the whole 90 minutes.

In a turnaround from the home team’s attempt to exploit the flanks, 46 per cent of Chelsea’s attacks ended up coming down our left wing, where Alonso - making his 200th appearance for the club - had four of our eight shots, although that statistic is slightly misleading as three of those came via set-pieces.