All match data from Stats Zone and Who Scored.
It is incredibly simplistic, but football is a game about space. Controlling space, utilizing space. Especially Liverpool's game.
No opponent bar Tottenham had given Liverpool any space in attack in 2017. And there's a very good reason for it. When you give Liverpool space, Liverpool can punish you. Liverpool are far more likely to punish you. And when you don't, Liverpool often suffer.
See: Liverpool's first two goals on Saturday.
In theory, Arsenal were set up to stop this. Giroud up front allows for more direct play out of defense, Welbeck and Oxlade-Chamberlain on the flanks are more defensive wingers, and Iwobi was central and basically playing as a third midfielder without the ball.
In practice, it didn't go so well, and it starts with defensive organization and controlling the defensive space.
All Liverpool had to do to get to this position was challenge for Mignolet's goal kick.
There's obviously still a bit to do afterwards, but it's far less likely this results in a goal if Koscielny doesn't charge out to contest the aerial with Firmino. He "wins" but it also skims off his head backwards, leading to a three-on-three, soon to be four-on-three with Firmino on the front foot and Arsenal's midfield plus Koscielny on the back. Coutinho lay-off to Lallana, Lallana wide to Mané, Mané able to center through retreating Arsenal players to Firmino, very much aided by Coutinho's dummy.
Then, 30 minutes later:
Milner gets a bit fortunate on the flank, but Arsenal break down as Iwobi doesn't track Wijnaldum, so Mustafi comes over, leaving Koscielny caught in two minds, whether to mark Firmino (also needed because Xhaka's late in getting back to help) or switch to Lallana, who's currently marked by Monreal. Which leaves Sadio Mané with more space in the penalty box than he even saw against Tottenham.
Liverpool still have to be clever enough, potent enough, and fortunate enough to take advantage, which hasn't always been the case during the winter of our discontent, even when given glimmers of openings. But it still goes back to the fact that Arsenal couldn't, didn't control their defensive space. And Liverpool used it.
Needing just nine minutes to make the breakthrough was also a massive boost.
Liverpool have now won ten and drawn just once in the 11 matches where they've scored before the 20th minute. 5-0 Burton Albion, 4-1 Leicester, 2-1 Chelsea, 5-1 Hull, 2-1 Tottenham (League Cup), 4-2 Crystal Palace, 2-2 West Ham, 1-0 Manchester City, 1-0 Plymouth Argyle, 2-0 Tottenham, and 3-1 Arsenal. In all but City and Plymouth they've gone on to score at least once more.
Granted, that's a small sample size in a low-scoring sport. The team that scores first wins fairly often no matter when it happens. Yes, even Liverpool. And "before the 20th minute" is something of an unfair dividing line, as Liverpool scored in the 20th minute at both Bournemouth and Sunderland, and went on to lose and draw respectively.
But still, an early goal seems to matter so much more to this side, in games against both good and bad opposition. There's Chelsea away and City, Tottenham, and Arsenal at home, but there's also 4-1 Leicester, 5-1 Hull, and 6-1 Watford – teams who've foiled and frustrated Liverpool in the last two months.
And the early goal meant Arsenal needed to open up and Arsenal tried to go back to doing what they do best. And Liverpool are fairly well set up to stop that.
Look at all those ball recoveries in the middle third, led by Milner (4), Clyne (3), Firmino (3), and Lallana (3).
Special mention need go to Adam Lallana, his crucial role in both the press and the finishing. Four of Lallana's five attempted tackles, as well as his lone interception, came in that span between Liverpool's two goals. He played a key part, and the second assist, in both Liverpool's first and third goals.
Few clips of Adam Lallana performance vs Arsenal. His work rate yesterday was simply outstanding... pic.twitter.com/ZBJwa06b7s— LFCMostar (@LFCMostar) March 5, 2017
Liverpool are incredibly dangerous when given the opportunity to press the opposition in the middle third. Most sides have tried to limit their ability to do so, especially in the last couple of months. Arsenal seemed set up to do so as well, but Liverpool's early goal made that much more a moot point.
With this win, Liverpool are almost certainly finishing first in the Top-6 mini-league. They've taken 19 points from nine games, five wins and four draws, with City away the only top-6 match left. Chelsea (two games left) or City (four games left) would have to run the table to finish on 19 points from these ten matches. At worst, Liverpool will average 1.90 points-per-game from matches against Chelsea, Tottenham, City, Arsenal, and United, and at best, they'll finish with 2.20. Either figure's impressive, especially when considering Liverpool's record against top sides under the previous manager.
The thing is, no matter how fun it is to beat your peers, it's often less important than you'd think. In the last ten seasons, only three winners of the top-six mini-league won the actual league: Manchester City in 2011-12 and Manchester United in 2006-07 and 2010-11.
You have to beat the dross to win the league. That's why Liverpool, still unbeaten against England's best sides with only one game left against them, are only clinging onto fourth.
Burnley on Sunday.