Chelsea manager Frank Lampard praised the maturity of his young squad after the Premier League club secured a vital 2-1 win away to Lille in the Uefa Champions League on Wednesday.
In-form striker Tammy Abraham celebrated his 22nd birthday with the opening goal, before Victor Osimhen equalised for French side Lille in the first half. Brazilian midfielder Willian then scored the decisive goal in the 77th minute with a well-taken volley as Chelsea got their first Group H points on the board following the home defeat to Valencia last time out.
Last year's semi-finalists, Ajax, lead the group on maximum points after an impressive 3-0 win at Valencia.
"Overall it was a good game. It's never an easy place to play. Give it to the team, what a fantastic performance," Abraham told BT Sport.
Lampard's team face Ajax next in Amsterdam and will do so with renewed belief after this potentially pivotal victory.
"It is such a tough place - the roof was on, the crowd were up for it, the speed in their team and on the counter-attack especially was very evident, so we had to be ready for it and I thought our performance was really good," Lampard said.
It was a game decided by one of the most experienced players on the pitch but which was bristling with exciting young talent as these clubs adjust to seeing their standout players - Eden Hazard on one side, Nicolas Pepe on the other - depart in the close season.
Lampard fielded two 24-year-olds as well as four more players aged 22 or under in his line-up, as teenager Reece James started as a right wing-back in a 3-4-1-2 system.
James only made his senior debut for the club a week ago in a League Cup tie against fourth-tier Grimsby Town and scored a wonderful goal in the 7-1 win. His second-half replacement, 18-year-old Callum Hudson-Odoi, set up the winning goal.
"This isn't a game for niceties, we have to go and win these matches and improve all the time and there were loads of signs of team improvement tonight, and individuals," Lampard said.
"The young players are responding and they have to keep doing it because the Champions League level is something else."
Much has been made of Lampard's promotion of youth this season in response to Chelsea's transfer ban, although their team also featured N'Golo Kante, with the France midfielder returning from his latest spell on the sidelines.
Indeed, the average age of Chelsea's team at kick-off was actually a year older than that of Lille.
Chelsea took a 22nd-minute lead when Fikayo Tomori's ball into the box was not dealt with by the home defence, and Abraham -- capped by England but eligible for Nigeria through his father -- emerged to control and fire home.
Lille actually looked the better side going forward for long spells and Luiz Araujo was denied by a good Kepa Arrizabalaga save just after the half-hour mark.
Moments later they were level, Bamba sending in a corner from the left for Osimhen, the gangly 20-year-old Nigerian striker signed in the summer, to head in his seventh of the campaign.
Jorginho struck the outside of the post with a first-time strike from range just before half-time, while Kepa tipped a Benjamin Andre header around the post early in the second half.
However, the introduction of Hudson-Odoi for James midway through the second half, and subsequent change of formation, breathed new life into the visitors going forward.
Mason Mount was denied by Mike Maignan soon after, and just 12 minutes remained when winger Hudson-Odoi crossed from the left all the way to the back post where Willian connected with a volley that bounced down into the ground, over the goalkeeper's head and in.
There was no way back for Lille, who have now failed to win any of their last 13 matches in Europe.