An embarrassing late blunder from Girona goalkeeper Paulo Gazzaniga gifted Paris Saint-Germain a 1-0 home win, denying the Champions League debutants a point.

After relentless PSG pressure, Nuno Mendes’s low ball across the goal looked comfortable for Gazzaniga, but he let it slip through his grasp and into the net in stoppage time, for an own goal that earned the hosts a victory that was deserved on the balance of play.

Girona’s defence effectively neutralised PSG’s attack in the first half but the French champions began to dominate in the second half. Ousmane Dembélé was denied by Ladislav Krejci’s last-ditch challenge and then hit the woodwork soon after the hour.

With the visitors seemingly happy to play for a draw, Randal Kolo Muani narrowly missed with a shot before Gazzaniga saved Achraf Hakimi’s close-range half-volley with his legs. Luis Enrique’s side registered 26 shots to Girona’s three, but looked set to be frustrated until Gazzaniga’s late gift.

Jamie Gittens scored two goals and Serhou Guirassy added a late penalty as Borussia Dortmund punished hosts Club Brugge for several wasted chances with a 3-0 win.

Last year’s beaten finalists rode their luck but grabbed the lead when English winger Gittens, on as a second-half substitute, struck in the 76th minute. Gittens picked up the ball on the left-hand side of the box and his angled shot took two deflections before ending up in the far corner of the net.

The 20-year-old made sure of the three points with a superb solo effort, running at the Brugge defence again before firing a low drive into the net. Dortmund added a third in stoppage time when another substitute, Serhou Guirassy, converted the penalty after being brought down in the area by Brandon Mechele.

Brugge will feel aggrieved, having struck the crossbar at 0-0 through Hugo Vetlesen and seen a couple of penalty appeals waved away. The Belgian side were also wasteful in front of goal, especially in the first half when they spurned several excellent chances to take the lead, paying the price when Dortmund found their feet late on.

Earlier, Sparta Prague returned to the Champions League in style, beating Red Bull Salzburg 3-0 in their first game in Europe’s top club competition for 19 years.

The Czech champions opened the scoring just two minutes in when Kaan Kairinen pounced on a loose ball after a great save by the Salzburg keeper, Janis Blaswich, to effortlessly slot home the rebound.

Victor Olantuji doubled the lead in the 42nd minute, firing in from a tight angle after a long ball from captain Filip Panak. Olantuji then set up Qazim Laci to make it 3-0 after a blunder by the Austrian side’s defence in the 58th minute.

Bologna were held to a 0-0 draw by visitors Shakhtar Donetsk, who missed an early penalty, in a lacklustre contest. The hosts were playing their first European Cup game since 1964 and conceded a penalty just four minutes in when Stefan Posch clumsily brought down Eguinaldo.

Heorhiy Sudakov’s penalty was saved by Bologna keeper Lukasz Skorupski, though, and it proved to be the best chance of a cagey game played in torrential rain. Bologna’s best two chances came either side of the interval, with Shakhtar keeper Dmytro Riznyk denying Santiago Castro and Giovanni Fabbian.

The first round of games in the new “league phase” are being played across three days, with six matches – including Atalanta v Arsenal, Monaco v Barcelona and Atlético Madrid v Leipzig – taking place on Thursday evening.