Liverpool must have thought for a moment that it was about to get a favor off Brentford, when David Raya fumbled a shot with Arsenal already a goal down. But the keeper recovered to save, and his team recovered to claim a big win — and Thomas Frank has now issued a stark warning about the title race.

Had Arsenal slipped up, Liverpool would have been nine points clear at the top of the Premier League with a game in hand, a position which would have felt about as close to unassailable as you can be on January 1. Instead, the Gunners can close the gap to three points by the time Arne Slot's men next take to the field against Manchester United, piling the pressure back on.

Admittedly, the chance for Arsenal to move within three is only a result of a quirk of the fixture calendar, along with the earlier postponement of the Everton game. Liverpool's "true" lead will be nine points if it can win its games in hand, which is still an enviable position to be in.

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But after seeing his Brentford team surrender its lead, Frank has predicted that Mikel Arteta and Arsenal could take the title race all the way. It's an assessment which Slot had already made for himself.

"It's a long season," Frank told Sky Sports. "I understand why Arne Slot is saying "we haven't won anything yet".

"Liverpool haven't had a dip yet and that will most likely come, and Arsenal are picking up points when they're not fully firing. It will go right to the end."

While Slot will be hoping to avoid any such dip, the Liverpool boss is well aware of the amount of football still to play. He has been remarkably level-headed since the moment he took charge, a trait which has no doubt helped with the daunting task of replacing Jurgen Klopp, and that isn't about to change now.

If nothing else, Liverpool still has to play Arsenal again. Assuming Arteta could engineer a win, Slot's margin for error would be slashed.

And the win over Frank's Brentford showed that Arsenal has more staying power than it may seem. Twice unable to keep pace with Manchester City in recent campaigns, Arteta's side has developed an unerring set piece threat, a powerful weapon in getting out of tight spots.

At the halfway mark, Liverpool has earned its position as the clear favorite, which is huge testament to the job Slot has done (and the work Klopp did before him). But the Frank warning will not have been necessary, with everyone well aware of the mammoth effort required to see the job through from here.

Liverpool.com says: Everyone has been hugely impressed with the job Slot has done in the first half of the campaign. If anything, maintaining a similar standard in the second half of his debut season would be even more impressive, so a continuation of such fine form certainly cannot be taken for granted.

The strong start has bought the Reds a little leeway, but even a lead of nine points can evaporate pretty quickly when a couple of wins turn to draws, and crucial head-to-head clashes go the wrong way. Slot knows that a "start" is all it is.

That's not to pour cold water on title hopes, with Liverpool deservedly starting to dream. But Frank is right: this may well still go all the way, with Arsenal not likely to be shaken off without a fight.