Raphinha continued his remarkable early season form with a brace as Barcelona demolished Feyenoord 5-1 to open their Champions League campaign in perfect fashion at a storm lashed Camp Nou on Wednesday.

A downpour hit the Catalan capital shortly before kick off, forcing supporters to scramble for cover, though it did little to slow Barcelona, who were already ahead by the time the rain eased early in the first half.

Raphinha broke the deadlock inside three minutes, cutting sharply into the box and leaving two defenders sliding the wrong way on the slick surface before finishing calmly past the goalkeeper.

Karim Adeyemi, deputising for Anthony Gordon, doubled the lead in the 22nd minute with a superb curling strike from outside the area that bent beyond Feyenoord goalkeeper Tjark Ernst.

Feyenoord briefly threatened a response through Anis Hadj Moussa, only for Joan Garcia to push his effort away at the near post.

Barcelona continued to carve out chances throughout, with defender Joao Cancelo nearly adding a third after beating Givairo Read before crashing a shot against the outside of the post.

Raphinha eventually got his second midway through the second half, running onto a perfectly weighted through ball from Pedri to slot home Barcelona's third in the 57th minute.

Feyenoord thought they had pulled a goal back moments later when Nacho Ferri found the net, only for the effort to be ruled out following a VAR review for offside in the build up.

Lamine Yamal added a fourth in the 77th minute, curling a free kick directly through a gap in the Feyenoord wall for his first goal of that kind for the club. The Dutch side introduced Shaqueel van Persie, the 19 year old son of former Netherlands international Robin van Persie, in search of a way back into the contest.

Sem Steijn did eventually reduce the arrears in the 82nd minute, escaping the attention of Jules Kounde to convert a dangerous low cross from Goncalo Borges.

It proved the only blemish on an otherwise dominant Barcelona display, with substitute Gabriel Jesus rounding off the scoring soon after, glancing home his first goal since arriving from Arsenal this summer via a Yamal cross.

The result extended Barcelona's perfect start to the season to five wins from five matches across all competitions, with the club netting five goals on four separate occasions during that run.

Raphinha, now operating up front following the summer departures of Robert Lewandowski and Ferran Torres, has settled into the role with remarkable speed, scoring eight goals in just five appearances.

Speaking to Movistar afterwards, the Barcelona captain credited the home support for helping drive the team's early season momentum.

"Playing in front of our fans we always have to show perfect football, or nearly perfect, and with the support of the fans it's a lot easier. I think we were very good, from the start of the game, controlling the game and with the chances we had we were able to score and it gives us a lot of confidence," he said.

Raphinha was nonetheless cautious about reading too much into the early results, pointing to the length of the season still ahead.

"In a season as long as this, there are many ups and downs. Starting the season like this obviously gives us a lot of confidence and we have to continue like this. We have to hope the downs are as small as possible," he added.

Head coach Hansi Flick made five changes to the side that had thrashed Valencia the previous weekend in La Liga, though he retained Yamal, Raphinha and new signing Rodri in his starting eleven for the European opener.

Elsewhere in the competition, Ermedin Demirovic scored a remarkable first half hat trick inside just 12 minutes as VfB Stuttgart beat Viking Stavanger 3-1.

Demirovic opened the scoring after 20 minutes with a close range touch, only for Viking, making their first ever appearance in the Champions League group phase, to level almost immediately through Zlatko Tripic's swift counter attack finish.

Demirovic restored Stuttgart's lead in the 26th minute before completing his treble six minutes later with a well struck hooked volley, sealing the win for the German side.