Barça victory 'important for Ukrainian football', says Shakhtar's Pusic
Shakhtar have played home games away from their Donbass Arena in Donetsk, now occupied by Russia, since 2014.
But playing the match hundreds of miles away in Germany did not prevent Danylo Sikan securing a famous victory over Barcelona with his dipping header in the 40th minute.
"Unfortunately, because of the situation in the country, you can call this a home game but for us it is a tremendous part -- the travelling, and sometimes we need one or two days extra to recover of course," said Pusic.
"It is not so easy... It is important also for Ukrainian football to represent the country in Europe like we did tonight."
Barcelona still lead Group H ahead of second-placed Porto, who beat Royal Antwerp 2-0, on head-to-head record, but missed the chance to wrap up qualification for the last 16 with two games to spare.
"After two years without qualifying for the last 16, today is a missed opportunity," said Barça coach Xavi Hernandez.
Shakhtar, on six points, gave their knock-out stage hopes a boost, but also put themselves in pole position to at least finish third ahead of Antwerp and move into the Europa League.
"If we achieve that (last 16), it would be fantastic. If not then to stay in Europe would also be a great achievement, amazing achievement even, for this club under those circumstances," added Pusic.
After failing to progress from the group stage for two seasons running, Barcelona had won their first three matches this term.
However Shakhtar held their own from the start.
Barcelona missed big chances in the first match in October but this time Pusic's team shut down their uninspired visitors, who produced just one shot on target.
Shakhtar forced Marc-Andre ter Stegen into the first save of the game, with the German goalkeeper denying Mykola Matviyenko at the near post after he got in behind Joao Cancelo.
Ilkay Gundogan and Raphinha lashed over from distance as Barça created no danger, with veteran striker Robert Lewandowski woefully disconnected on his return to Germany.
The former Bayern Munich forward has not scored in any of his last six appearances for Barça, amounting to his worst run of goalscoring form for over a decade.
Sliced open
The hosts took the lead a few minutes before half-time, easily slicing the visitors open when Giorgi Gocholeishvili took advantage of Barcelona left-back Marcos Alonso being a long way out of position.
The full-back crossed for Sikan, who beat Andreas Christensen in the air and headed beyond the reach of Ter Stegen.
Ter Stegen saved from Gocholeishvili early in the second half as Shakhtar continued as they left off.
Just before the hour Xavi took action, sending on speedsters Alejandro Balde and Lamine Yamal, as well as Pedri, looking to shake up his team's lifeless display.
Barcelona were better but not bright enough, as Shakhtar goalkeeper Dmytro Riznyk enjoyed a quiet night.
Shakhtar's latest young Brazilian winger, Newerton, scored a stunning second in the final stages but it was chalked off for offside -- it would have been a superb way to crown a glorious night for Pusic's men.
Barcelona had seven minutes of added time to work with but could not find a breakthrough, with Felix unsuccessfully appealing for a penalty after he was clipped on the edge of the box.
The Ukrainian champions, third, celebrated joyously at full-time and now sit only three points behind Barcelona, who host Porto in their next Champions League match on November 28.
"We do things step by step and we stay humble," said Pusic, who was proud of his team's defensive effort.
"We like to attack and we had several good moments tonight, but game organisation comes first.
"If you concede easily at this level there is not a high chance you will win."
Barcelona midfielder Oriol Romeu said his team had to look in the mirror after their disappointing display.
"Every defeat is a warning," he told Movistar.
"We have to be self-critical and see what we did wrong, to correct it quickly."