It was a dramatic opening night in the Champions League, with Juventus and Borussia Dortmund sharing eight second-half goals while Qarabag shocked Benfica.

Dusan Vlahovic and Lloyd Kelly scored in stoppage time to inspire a dramatic Juventus escape, as they secured a 4-4 draw in a game where all eight goals came after the break.

The hosts trailed 4-2 when Vlahovic struck his second of the night in the fourth minute of stoppage time and Kelly completed the comeback two minutes later to secure a share of the points.

After a quiet first half, Dortmund found the breakthrough eight minutes after the restart as Karim Adeyemi rifled a precise shot into the far corner from just outside the box. The hosts drew level in the 63rd minute through Kenan Yildiz, who collected the ball on the edge of the area, steadied himself and bent a superb shot into the far corner to ignite the Juventus fans.

The celebrations were short-lived, however, as Felix Nmecha restored Dortmund’s advantage barely two minutes later with a crisp first-time finish from distance.

The game’s tempo showed no sign of slowing, and by the 68th minute Juventus were level once more, Vlahovic racing on to a perfectly weighted pass to slot past Gregor Kobel in Dortmund’s goal.

The frenzy continued in the 74th minute, when Yan Couto’s low strike squirmed between Michele Di Gregorio and a post to put Dortmund back in front. The visitors were awarded a penalty four minutes from time, after Kelly was penalised for handball with Ramy Bensebaini converting from the spot. Deep into stoppage time, Vlahovic struck again from a well-placed cross before turning provider for Kelly, who headed in the equaliser to cap a second half to remember.

Vlahovic told Sky Sport: “To prove yourself you always need hunger. I’m never satisfied and tonight I wanted a third goal. The important thing is we didn’t lose, so we keep moving forward.”

Benfica let slip an early two-goal lead to lose 3-2 at home against Qarabag, with Oleksiy Kashchuk scoring the Azerbaijani side’s winner four minutes from time.

The hosts looked in control when Enzo Barrenechea put them ahead in the sixth minute with a glancing header from a corner and Vangelis Pavlidis shot on the turn to double the lead 10 minutes later. Leandro Andrade smashed a first-time shot past Anatoliy Trubin, however, and Qarabag came close to drawing level when Kady Borges hit the post and Trubin made an excellent save from Marko Jankovic’s follow-up effort.

Qarabag were level three minutes after the interval when Camilo Durán ran on to a defence-splitting pass from Marko Jankovic and smacked a first-time shot into the far corner but the visitors were not done yet.

A long punt forward from the Qarabag goalkeeper found Kashchuk just outside the area and he played a one-two with Abdellah Zoubir before stroking a shot past Trubin to stun the Estadio da Luz.

Belgium’s Union Saint-Gilloise made a dream debut in the Champions League league phase by stunning PSV 3-1 in a feisty Low Countries derby in Eindhoven.

Union, who won the Belgian title for the first time in 90 years last season, secured their first points as Promise David converted an early penalty and Anouar Ait El Hadj ran half the length of the pitch to add a second before the interval.

The defender Kevin Mac Allister bundled home the third 10 minutes from time, forcing the ball over the line with his knees from a corner, to complete a shock result.

PSV grabbed a last-minute consolation through Ruben van Bommel but it failed to put any gloss on a miserable night for the Dutch champions.

Elsewhere, Arsenal won 2-0 at Athletic Bilbao, Tottenham edged past Villarreal 1-0 and Real Madrid came from behind to beat Marseille 2-1.