Barcelona are unstoppable, untouchable and simply irresistible. In 17 games they have scored 91 goals and conceded four, and they barely stepped out of second gear as they humbled Arsenal to cruise into the quarter-finals of the Champions League. The Arsenal midfielder Kim Little described the defeat as a “slap in the face” but an “incredibly helpful” test nonetheless. “It really allows you to see where the level is at, and where we need to aim for,” she said. The Gunners have the tough task of rebuilding confidence before this weekend’s home game against Leicester and next week’s crucial final Champions League group game against Hoffenheim, which will determine who progresses alongside the Catalan club. “Football is also momentum,” said their manager, Jonas Eidevall, when asked how they will protect the morale of the group. “We have to take away the things we can learn and develop. At the same time we mustn’t forget the things we’ve done really well so far this season ... It will be extremely important for us to get back on track and to not let this define us. “Everyone understands what needs to be done but everybody has to live by it.” The mood among the home support before kick-off was less about whether Arsenal would challenge and more about the size of the margin between the two sides. Such is the dominance and superiority of the Spanish champions that simply not being humiliated becomes the primary goal and, terrifyingly, that is almost as hard to achieve as emerging victorious. There were some positives to take from the first half. Despite trudging back to the dressing room three goals down at the break, Arsenal did not start badly. They pressed slightly higher up the pitch than they had in the reverse fixture in Spain, which they lost 4-1, played with energy and managed to pull off a few smart breaks. But those moments in attack were fleeting and Barcelona looked unfazed. They were prepared to let Arsenal have a little more of the ball – just enough, like a parent allowing their child beat them in one of five card games so as not to appear too cruel. The first goal was particularly bruising because it was utterly avoidable. The Arsenal centre-back Jen Beattie’s pass ran short and both the goalkeeper Manuela Zinsberger and the stand-in centre-back Steph Catley backed away, each presumably thinking the other would collect it. Instead Aitana Bonmatí slipped forward, outran the recovering Catley and slotted coolly past Zinsberger into the far corner. Conceding seemed to suck the life out of the Gunners a little – not quite to the extent that Fran Kirby’s early strike for Chelsea preceded total collapse in last weekend’s FA Cup final, but they looked slightly deflated. Seven minutes later they failed to deal with a cross from the left-back Frida Rolfö, with Beattie not quite getting her head to it, and Jenni Hermoso was on hand to fire in from close range. On the stroke of half-time it was three, thanks to a goal befitting the classy holders. Rolfö took advantage of a heavy pass from Nikita Parris to Jordan Nobbs to take possession on the edge of the box before rounding Frida Maanum and bending a right-footed strike around Zinsberger. Conceding three to Barcelona is standard fare; only one team, the Danish side HB Køge, have conceded fewer this season, with the bottom side in Group C having lost 2-0 to the champions in October. To try to dispossess the experts of close control requires numbers, so while sometimes three red shirts would labour to poke the ball from the feet of one, a visiting player was the first to every second ball, making the hard work meaningless. Scarily this was far from Barcelona at their best, as their ruthless performance in the reverse fixture demonstrated. But it didn’t need to be. Still they provided the greater threat. Moments after a smart double stop, Zinsberger’s outstretched hand pushed away Caroline Graham Hansen’s low cross but Hermoso was at the back post to fumble the ball over the line. Fortunately, the result matters little as a point against Hoffenheim next week will send the Gunners through, and Barcelona have shown them the levels they need to reach. “We’re all learning and developing through [these new Champions League group games],” said Eidevall. “It’s great even if it doesn’t feel good losing 4-0.”