It was over two years ago when Chelsea were dismantled by an imperious Bayern Munich side at Stamford Bridge 3-0. It was on that very chilly February evening where the gap to Europe's elite was laid bare.
The finishing of Serge Gnabry in particular felt a level above anything the Blues had faced that season. A lot has changed since that night, most notably a majority of the squad humbled by Bayern going on to win the Champions League the next year.
But against Real Madrid on Wednesday night there was another demonstration of quality Chelsea have been aspiring to, this time from Karim Benzema. For all of Tuchel's annoyance with the level of his team's display, the Frenchman put on a masterclass of centre-forward execution.
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It started within the opening 10 minutes when Benzema drifted over to the right-wing to begin a Real attack. Closed down by both Cesar Azpilicueta and Thiago Silva, Benzema lures both in before playing a reverse pass into the feet of Federico Valverde that opens up the pitch. The move leads to Vinicius Junior receiving the ball on the left, whose right-footed effort smacked the bar.
Benzema's first goal was a superb header, a late run into the box to perfectly connect with Vinicius' cross, drilling the ball beyond Edouard Mendy's reach. However, it was his involvement in the build-up that again reflected his elite quality.
Dropping deep to play a one-two with Toni Kross before receiving a pass from Vinicius and playing the Brazilian through beyond the Chelsea backline.
The second goal is equally superb from the 34-year-old, dropping deeper again in the build-up before ghosting in between Andreas Christensen and Thiago Silva to meet Luka Modric's cross that again beat Mendy.
His third was purely down to Mendy's horrendous error in a miscommunication with Antonio Rudger, allowing Benzema to round off his hat-trick in a simple fashion and most likely kill off the tie.
Benzema's own xG of 1.03 at full-time was not far behind Chelsea's overall score of 1.64. The gap in productivity is most demonstrated by wider stats.
Chelsea had 20 shots compared to Real's eight, the same number on target and slightly more possession. This was a slight role reversal of the tie at Stamford Bridge last May, where Chelsea overwhelmed Real despite only having 32% possession.
Most damning was the later introduction of Romelu Lukaku, bought for nearly £100m last summer to solve the Blues' profligacy, missing a simple header from five yards out to make the game 2-3.
It is probably more reflective of how Lukaku's Chelsea return has gone that he was sat on the bench for this glamour tie, while the younger Kai Havertz led the line and scored.
The silky German was Chelsea's standout performer on the night, constantly looking to harass the Real defence, making darting runs behind and taking aim at Thibaut Courtois' goal when possible.
His header sprung the home crowd into life and continues his fine run of scoring since the beginning of March. Havertz is slowly showing the clinical traits Chelsea have required for some time, a project Tuchel should be sticking with in the remaining weeks of this season. But Benzema's tally of 37 for the season proves how costly profligacy can be at this stage of the competition.
