Barcelona hit nine in Women's Champions League, Arsenal beat Valerenga
Holders Barca routed their Swedish opponents in Catalonia, putting down a marker after slumping to a shock loss to Manchester City last week.
Goals by Caroline Graham Hansen, Claudia Pina and Alexia Putellas put the hosts in charge by half-time.
Mapi Leon added a fourth and Pina and Graham then doubled their tallies either side of an Ewa Pajor strike, before Esmee Brugts and Fridolina Rolfo completed the rout.
"I'm very content with the match because we kept our level for 90-plus minutes," said Barca coach Pere Romeu, according to UEFA's website.
"It's a mark of their champion mentality that they were ruthless when the game was won."
Graham opened the scoring after 10 minutes and Pina struck on 24 minutes, before Putellas was left free in the box to glance in Barça's third just before the interval.
Leon headed in on 53 minutes as the second-half floodgates opened with four goals coming in the space of 22 minutes.
A 90th-minute penalty by Sweden's Rolfo meant Barcelona equalled their 9-0 Champions League thumping of Benfica in 2022.
Man City came from behind to beat St Poelten 3-2 in a topsy-turvy encounter in Vienna thanks to goals from Alanna Kennedy, Aoba Fujino and Mary Fowler.
Kennedy sent City 1-0 up on five minutes with a fierce drive from 35 yards that veered away from the goalkeeper's lunge on its way into the net via the post.
The hosts struck back as City failed to deal with a corner and Melanie Brunnthaler pounced in the 40th minute.
The Austrians then took a surprise lead eight minutes after half-time when Kamila Dubcova volleyed into the top corner.
But Japanese forward Fujino opened her account for the visitors just four minutes later and then with 10 minutes remaining, Fowler rose highest to head the winner and send City top of Group D on six points.
'Long way to go'
Goals either side of the break from Linda Dallmann and Pernille Harder earned Bayern Munich a narrow win in north-eastern Italy.
With two wins from two, German champions Bayern sit top of Group C, three points clear of Arsenal in second spot.
"We have started very well, but the work is not done. We've played Arsenal and Juventus, two strong teams, but there's still a long way to go," said Bayern coach Alexander Straus.
Bayern broke Juventus resistance in the 18th minute when Dallmann managed to hack the ball over the goal-line from close range after it had ricocheted around the box following a corner.
In the second half, Juventus went forward in search of an equaliser with Bayern seeking to stifle the opposition and see out the match.
However, Juve's defensive set-piece woes allowed the away team to seal victory in the 73rd minute as Harder fired in her fourth goal of the campaign from a corner.
Arsenal got their campaign back on track after losing to Bayern first time out as they beat Valerenga 4-1 at the Emirates Stadium, in their first match since the departure of coach Jonas Eidevall.
Emily Fox gave Arsenal the perfect start after barely 61 seconds when she swept home from inside the six-yard box.
The hosts doubled their lead on 29 minutes through Caitlin Foord, before Olaug Tvedten halved the deficit 10 minutes before half-time but Mariona Caldentey and Alessia Russo struck late to make safe Arsenal's first win of the campaign.
On Thursday, Wolfsburg host Lyon in a clash of two multiple past winners of the tournament and English champions Chelsea travel to Twente.
