When Alisson limped off in the first half against Norwich City on the opening day of the Premier League season, Liverpool fans rightly feared the worst.

The Brazilian has arguably been the best goalkeeper in the world over the last 12 months and was instrumental in Liverpool amassing 97 points in the top flight while lifting the European Cup for the sixth time in the club’s history.

Replacing him was supposed to be a near-impossible task.

Yet summer signing Adrián, who arrived on a free having been released by West Ham United, has stepped up impressively. So much so that Alisson’s absence has yet to be truly felt.

Liverpool are top of the Premier League having won all six of their games this season. Along with Leicester City, Jürgen Klopp’s men have conceded the fewest number of goals (5) while only three teams can boast a better expected goals against total.

Manchester United lead the way (3.84), with Leicester not far behind (5.54). Manchester City have an expected goals against total of 6.11 while Liverpool’s is 6.59. The Red Devils are underperforming this metric having conceded six times. The Reds are 1.59 better off.

Only three teams can better Liverpool’s overperformance – Newcastle United, West Ham and Bournemouth. However, Adrián's exploits are more remarkable when considered he’s not as busy as the shot-stoppers at the three aforementioned clubs.

Given the small sample size, it’s easy to stand out at this stage of the campaign. And for context, Newcastle’s expected goals against average this term is 1.6 yet they’re facing 15 shots per 90. Sooner or later, Steve Bruce's side will suffer a big defeat as such overperformance isn't sustainable.

Likewise Bournemouth. Their expected goals against average if 2.05 and they’re allowing the opposition to have 16 shots per 90.

Meanwhile, Liverpool, on average, are only facing ten shots on a per 90-minute basis with an expected goals against total of 1.09.

Last season, the Reds outperformed their expected goals total by 7.15. Others bettered it but it was down to the volume of shots faced. Liverpool limited the opposition to the extent that when Alisson was forced into action, it was a significant moment.

On a per 90 basis, the difference between goals conceded and expected goals conceded was 0.18. In the six Premier League games so far this term, the average is, once again, 0.18.

WHAT A SAVE!! On his Champions League debut, Adrian has just pulled one right out of the top drawer to deny Dries Mertens ? pic.twitter.com/D603fCTeal — Football on BT Sport (@btsportfootball) September 17, 2019

Liverpool are perhaps a little worse as a defensive unit – goals conceded are up as is expected goals against – but this could be down to the team adapting to a higher defensive line.

The main takeaway, however, is that they’re overperforming their expected numbers at an identical rate to last season. Alisson’s injury could have been detrimental to Klopp’s pursuit of the Premier League campaign. Instead, his absence hasn’t been felt.

Adrián hasn’t just made routine saves either. He’s pulled off stops right out of the top draw while ensuring the basics are ticked off.

The former West Ham man displayed his reflexes with a stunning save against Southampton. He thwarted Nicolas Pépé against Arsenal and stood tall to deny Tammy Abraham at Chelsea. They were alls big saves games that Liverpool went on to pick maximum points from.

Arguably his best was during the defeat to Napoli when he somehow kept out Dries Mertens’ point-blank effort. He didn’t just make himself big and allow the ball to hit him, he redirected his hand while in mid-air to ensure he could save it.

It was a world-class stop and it kept Liverpool in the game. In the end, it counted for little with the Reds losing 2-0, but that doesn’t detract anything away from the exceptional save.

The turnaround in Liverpool's goalkeeping fortunes is remarkable. It went from being a problem area to perhaps being the position they have the most strength in depth.

Alisson is one of the best in the world and you'd be hard-pressed to find a better back-up than Adrian.