Chelsea took one step into the quarterfinals of the Uefa Conference League with a 2-1 win at Copenhagen on Thursday in their last 16 first leg tie, while Panathinaikos and Fiorentina played out a five-goal thriller.
Reece James and Enzo Fernandez netted in the second half, before Gabriel Pereira halved the deficit for the hosts, as Enzo Maresca's side just did enough to take control of the tie in the Danish capital.
"Copenhagen are a good team, they play good football, have a skilled coach, and have many talented players," said Maresca.
"I'm always nervous, but right now, the focus is on our next matches. The return leg will be another tough game."
Following an uninspiring opening period, Chelsea skipper James broke the deadlock one minute after halftime when he strode onto Marc Cucurella's deep cut-back and rolled an effort from distance inside the near post.
The goal brought the game to life and Copenhagen nearly struck back instantly, only for Viktor Claesson to see his one-on-one effort come back off the inside of Robert Sanchez's post and into the goalkeeper's grateful arms.
Halftime substitute Fernandez made the game safe for the visitors with an emphatic 65th-minute finish following good work by teenager Tyrique George.
The Premier League side were cruising until 11 minutes from time when Pereira was left unmarked in the box to nod in from a set-piece.
"When you go to Stamford Bridge (Chelsea's stadium) and need to win a game by two goals, you need a little miracle," said Copenhagen coach Jacob Neestrup.
"The belief is there. It's not the best possible result, but it is what it is."
'HARD WORK'
Elsewhere, last season's defeated finalists Fiorentina went down 3-2 to Greece's Panathinaikos.
The Greek hosts flew out of the traps, racing into a 2-0 lead inside 19 minutes courtesy of Karol Swiderski and Nemanja Maksimovic.
But within just four minutes, Fiorentina were back level after two rapid-fire strikes from Lucas Beltran and Nicolo Fagioli.
Tete restored the hosts' lead ahead of the second leg with a sweeping, left-footed finish in the 55th minute.
"This is the result of our hard work," said the Brazilian match-winner.
"We took a 2-0 lead, but they levelled through our errors. I am very happy that I got to score the winning goal."
Molde held on to win by the same scoreline against Legia Warsaw in Norway.
Eirik Hestad scored a neat opener on 11 minutes, before Kristian Eriksen doubled up six minutes later.
Fredrik Gulbrandsen raced onto a fine through ball from Emil Breivik to add a third shortly before the interval.
Kacper Chodyna and Luquinhas scored two in three second-half minutes to drag the Poles back into the tie.
LaLiga club Real Betis drew 2-2 at home to Iberian neighbours Vitoria Guimaraes of Portugal.
Rapid Vienna were held 1-1 in Bosnia and Herzegovina by Borac Banja Luka after David Vukovic scored a 92nd-minute penalty to level for the hosts.
Three second-half goals for Jagiellonia Bialystok gave the Poles a 3-0 home win over 10-man Cercle Brugge.
Swiss side Lugano went down 1-0 in Slovenia against Celje, and Pafos of Cyprus won by the same margin at home to Sweden's Djurgarden.
The second legs will take place on March 13.
RESULTS
LAST 16, FIRST LEGS
Real Betis (ESP) 2 (Bakambu 48, Isco 75) Vitoria Guimaraes (POR) 2 (Saraiva 51, Nelson Oliveira 81)
Molde (NOR) 3 (Hestad 11, Eriksen 17, Gulbrandsen 43) Legia Warsaw (POL) 2 (Chodyna 64, Luquinhas 67)
Copenhagen (DEN) 1 (Pereira 79) Chelsea (ENG) 2 (James 46, Fernandez 65)
Panathinaikos (GRE) 3 (Swiderski 5, Maksimovic 19, Tete 54) Fiorentina (ITA) 2 (Beltran 20, Fagioli 23)
Borac Banja Luka (BIH) 1 (Vukovic 90+2-pen) Rapid Vienna (AUT) 1 (Beljo 34)
Jagiellonia Bialystok (POL) 3 (Pululu 69-pen, 78, Romanczuk 75) Cercle Brugge (BEL) 0
Celje (SLO) 1 (Svetlin 23) Lugano (SUI) 0
Pafos (CYP) 1 (Tankovic 65) Djurgarden (SWE) 0
