Graham Potter urged Chelsea to not "wait around for luck" but hailed a "dominant" performance despite a slender defeat at Borussia Dortmund in the Champions League last 16.
Karim Adeyemi's third goal in as many games for Dortmund in all competitions, one more than in his previous 20 appearances, proved the difference in a narrow 1-0 win at Signal Iduna Park on Wednesday.
Chelsea should have arguably been out of sight before Adeyemi's 63rd-minute strike, with Joao Felix squandering a pair of glorious first-half opportunities in an entertaining encounter.
Gregor Kobel had a fine game in goal for Edin Terzic's side too, and Potter appeared far from worried after an encouraging display ahead of the return meeting at Stamford Bridge on March 7.
The Chelsea head coach told BT Sport: "I thought we were the dominant team in the second half.
"It is half-time in the tie, we have to regroup. You can see the supporters' reaction, they were really positive, they can see the performance of the team, they gave us a fantastic reception.
"We are a team in progress, we know there are a lot of positive things there.
"You always need a bit of luck but you can't wait around for luck, you have to keep working.
"The boys have been fantastic with their work but we are still suffering at the moment. But we will keep on working."
Visiting Chelsea had 21 shots to their hosts' 14, with six more on target than Dortmund's two, as the Blues dominated without reward in Germany.
Potter's side amassed an expected goals tally of 2.14 to the 1.41 of Terzic's men as well, although all that mattered was Adeyemi's brilliant finish after a roaring counter-attack from a Chelsea corner.
Struggles in front of goal are not a new problem for Potter, with Chelsea managing just four goals in nine matches in all competitions and failing to score in five of those games.
The Blues have drawn a blank in more outings in 2023 than any other Premier League club, yet Potter was pleased with what he saw – apart from Adeyemi's ruthless finish.
"It was a very strong performance, especially the second half," he added. "We created a lot of chances and efforts on goal but I am disappointed with the goal we conceded.
"It is a counter-attack from a corner, we were close to scoring ourselves. They broke on us. It is disappointing, we need to do better.
"Apart from that, we were really, really good, we just have to score. We had good attacking movements, clarity in terms of how we wanted to attack and got into the right areas. The attitude was really positive as well."