It’s still raining down here in the South, but I imagine no amount of rain is going douse the flames of Will Grigg. He’s on fire, don’t you know.

Having bemoaned the predictable weekend of cup action, it was timely for the old competition to wave its magic wand again. League One Wigan knocked out the all-conquering Manchester City.

The game itself is what many would describe as a “classic Football Manager” match. City had all the possession and all the chances, but between their own wastefulness and Wigan’s beaver-like defending they couldn’t find the breakthrough. Then, a single mistake from Kyle Walker gave Grigg the opportunity, which he took with the expected class of a striker who has his own song.

It was a game of high emotion, too. Pep Guardiola and Paul Cook had an animated discussion about Fabian Delph’s red card tackle that seemed to continue into the tunnel at half-time. In fairness, Guardiola would concede after the game that the challenge deserved a red. Then there was that business with the fans and police after the game.

I don’t mind a good pitch invasion, especially if it’s an outpouring of positive emotion. I was always under the impression that Wigan was a rugby town, and that its football fans weren’t quite as passionate, but they demonstrated a raw joy that clearly proved me wrong. It’s a pain for the stewards and organisers, but as long as nobody gets hurt in the end, I don’t see too much of a problem with it.

From a health and safety stand-point, though, nobody wants to take a chance, and I totally understand why some condemn it. Just as there were Wigan fans innocently enjoying themselves, there was angry City fans ripping up advertising hoardings, perhaps because they felt their own players were under threat.

In any case, fines will be dished out. Wigan won’t mind because they have a cup quarter-final to look forward to now. Southampton may be Premier League opposition, but Wigan will fancy themselves of pulling off another upset.

With the FA Cup over for a little while, attention turns to the Champions League.

Tonight, Barcelona will play Chelsea at Stamford Bridge. English clubs have done well in Europe this season, but this tie is by the hardest of the five still in the Champions League, and I really can’t see Chelsea winning.

This Barcelona side has travelled under the radar. They’re unbeaten in 24 league games, yet come across as more highly functional than stylish like they did in previous seasons. This is no longer the press-and-pass-to-death Barcelona that was feared and admired when Guardiola was in charge, nor does it carry the menace of Neymar, Luis Suarez and Lionel Messi like it did under Luis Enrique. But it’s a side that still has Messi and Suarez, and that’s all it really needs.

By far the most interesting thing about them is their formation. Ernesto Valverde has them playing a 4-4-2, usually in a diamond shape. Paulinho, a flop at Tottenham a few years back but a sensation in China, plays at the tip and has scored eight goals this season. It’s a radical change from the usual 4-3-3.

For Chelsea, wins over West Brom and Hull will give them a bit of a lift, but I’m not convinced they have enough quality to win the tie. It’s been some time since the last Antonio Conte masterclass, and he’s going to need N’Golo Kante to return to superhuman levels if he wants to keep the Barcelona midfield at bay. All eyes on Eden Hazard, too, and how he fares against elite opposition.

This is a fixture stacked with recent history, from Andres Iniesta’s late winner in 2009 and the controversy with referee Tom Henning Ovrebo, to Fernando Torres’ winning in 2012 on the way to the final, all to the backdrop of Gary Neville’s squeaky victory cry. Hopefully, another memorable moment will be on its way.