London - Frank Lampard faces the first major test of his nascent managerial career after Chelsea were given a chastening Champions League lesson by Bayern Munich.
Lampard's side are on the verge of crashing out of Europe's elite club competition following Tuesday's 3-0 home defeat against the German champions in the last-16 first leg.
Serge Gnabry's second-half brace and Robert Lewandowski's late strike underlined the gulf in class between a Chelsea team experiencing growing pains in Lampard's first season and a Bayern side packed with Champions League experience.
Four of the Bayern team that outplayed Chelsea at Stamford Bridge were members of the German club's 2013 Champions League final-winning team.
That wealth of knowledge was clear to see as Thomas Muller ran the show in midfield, while Lewandowski, who played in that final for Bayern's opponents Borussia Dortmund, was a constant menace.
For Chelsea to reach the levels set by Bayern, Lampard knows he needs to oversee a lengthy rebuild that will require patience - a quality not usually shown by the club's notoriously fickle owner Roman Abramovich and his advisors in the boardroom.
"This is Champions League football. We as a club haven't been fighting to get to the latter stages for a number of years and that's the level we have to get to," Lampard said.
"This was a clear show that there is a lot of work to be done. I felt that when I took the job. I will keep working."
Lampard is only just finding his feet as a manager and deserves time to put his stamp on a Chelsea team that has shown flashes of excellence this season.
They have impressed in wins against Tottenham, Arsenal and Ajax, but have flopped in a succession of uninspired home defeats.
His hand forced by Chelsea's transfer ban last summer, Lampard's first major decision after arriving from Derby, where he started his managerial career last term, was to put his faith in the club's cadre of talented youngsters.
Tammy Abraham, Mason Mount, Fikayo Tomori and Reece James have all shone at times.
But Chelsea's kids remain far too raw to be expected to be thrive against teams of Bayern's calibre.
Lampard acknowledged that fact by starting with Abraham on the bench on Tuesday and leaving Tomori out of the squad, instead using immobile veteran Olivier Giroud up front in a gamble that backfired.
Against Tottenham on Saturday, the average of Chelsea's starting line-up was 28 years and 171 days, the oldest team Lampard has selected in the Premier League.
In their 1-0 win at Ajax in October, the average age of his team was 25 years and 71 days.
After turning to his old guard when it came to the crunch, Lampard will have been frustrated that two of his senior players, Jorginho and Marcos Alonso, lost their heads.
Alonso was sent off for lashing out at Lewandowski and Jorginho earned a needless booking for arguing with the referee, which rules him out of the second leg.
Lampard was not helped by Chelsea's failure to make any signings in the January transfer window, although Hakim Ziyech agreed a deal that will bring him from Ajax in the close-season.
Injuries to N'Golo Kante, Christian Pulisic and Callum Hudson-Odoi have put further strain on Lampard's squad.
Chelsea are desperately short of guile and pace in the final third, while their central midfielders are far too predictable.
Lampard tried to plug the holes in a leaky defence by deploying Antonio Rudiger, Andreas Christensen and Cesar Azpilicueta as a back three.
The experiment had worked against toothless, injury-hit Tottenham, but Bayern posed a more formidable threat.
With their Champions League campaign in tatters, Chelsea must regroup for a final push to qualify for next season's tournament.
Sitting in fourth place in the Premier League, Chelsea's destiny is in their own hands.
"It was a harsh lesson. I learned about my players. We have to show character. They need to use it to positive effect," Lampard said.