Inconsistency reigns supreme as Manchester United host Arsenal in a blockbuster clash at Old Trafford.
The Red Devils are capable of beating an in-form team like Leicester City, yet Ole Gunnar Solskjaer's men are just as likely to need a penalty shootout to get past League One Rochdale in the cup.
Unai Emery and his recruits are similarly unpredictable, endlessly frustrating their supporters. Secure a 3-0 victory at Eintracht Frankfurt? Yes please. Lose a two-goal lead against winless Watford? Bread and butter stuff right now.
Here's seven statistics and facts to give you more of an insight into who's better placed for Monday's meeting.
Theatre of Screams
You have to go back to 2006 for the last time the Gunners triumphed on their rivals' turf, an era when Snow Patrol were top of the charts and these two were still fighting at the top of the table!
Double, Double, Toil & Trouble
2006/07 was clearly a profitable campaign for Arsenal against United, the Londoners doing the double under Arsene Wenger.
Since then, they are yet to register consecutive league victories over the Red Devils, though they have the opportunity to set that record straight after earning a 2-0 win in March.
An Exclusive Club
If the Gunners do inflict a second successive defeat, Solskjaer will gain membership to a very exclusive group of United managers... though he likely won't want it.
Only three other Red Devils coaches have lost their first two league encounters with Arsenal, and you have to go pretty far back in history to find them.
James West (1900), Timmy Docherty (1973) and Dave Sexton (1977/78) will be Solskjaer's company should his recruits fall flat on Monday.
The Red Devils have been beaten in half of their last six Premier League home games, going down to Crystal Palace, Cardiff and Manchester City. Just two victories have come in that time, Leicester and Chelsea the unlucky pair.
Old Trafford was once an impenetrable fortress, a place where visitors were torn limb from limb. Nowadays, you can pretty much waltz into United's castle and retrieve the three points at your leisure - the guards would probably give you a hug on your way out, too.
A few Jesse Lingard stats have been flying about recently, but almost none of them have been positive for the midfielder.
However, he can take plenty of heart from his track record in matches with Arsenal. The England international has scored a total of four goals versus the Gunners in his career, making them his favourite club to play against, statistically-speaking at least.
When Pierre-Emerick Aubameyang is around, the goals flow freely. He has netted 13 in his last 13 starts for Arsenal, the striker proving his employers were right to pay Borussia Dortmund £56m for his services in 2018.
Moreover, Aubameyang's tally of six goals this term is the most by any Gunners player at this stage of a Premier League season since Emmanuel Adebayor in the autumn of 2007. Top quality forwards have been hard to find/keep, it seems.
Fix That Leak
When you think of Arsenal's defence, solidity and reliability are two words that probably don't come to mind.
The Gunners have conceded at least two goals in each of their last four league fixtures, a rather alarming stat for Emery to mull over. They haven't shipped two goals in five successive games since 1985 - best not pick Shkodran Mustafi, then.