Liverpool produced another performance on Sunday afternoon that showed just why Brendan Rodgers feels he has a side capable of challenging for a top four finish - but is Pepe Reina becoming too much of a liability?

Away from home against the reigning Premier League champions, Liverpool put in one of their finest performances of the entire campaign. They harried and harassed the City players throughout and consistently looked a threat whether counter-attacking at pace, or through the sublimely skilful duo of Daniel Sturridge and Luis Suarez in attack.

Liverpool enjoyed more possession [56%] and had a total of 21 shots on goal, compared to City's nine. Almost every statistic available was in their favour, yet they once again failed to gain three points. It was déjà vu for Rodgers who earlier this season had seen his side outplay Manchester City but only gain a point after an error from Martin Skrtel allowed Carlos Tevez to equalise.

Too many times this season a defensive lapse has cost Liverpool, and unfortunately a number of these errors have been from their number one Pepe Reina.

The Spanish keeper was once viewed as one of the most reliable stoppers in the Premier League but in recent seasons that has changed. He has often looked nervous and no longer seems to command his area, while even his handling has been poor on a number of occasions in this campaign.

Against Manchester City it was another kind of error which cost Liverpool. This time it was poor judgement as his decision to follow the run of Sergio Aguero proved disastrous as the diminutive forward finished from the tightest of angles. It was a sensational goal but one that could have been avoided.

Football statisticians Opta were quick to point out that this was the latest in a long line of mistakes over the last 18 months which had led directly to a goal.

"8 - Since the start of last season Jose Reina has made eight errors leading directly to a goal in the Premier League. Misjudge," tweeted OptaJoe.

Previously there had been a suggestion that Reina was merely going through a bad spell. He even admitted in a recent interview with Spanish newspaper Marca that this has been his most difficult season in England.

"This has been the most unsettled season, both personally and as a team, since I joined the club," said Reina. "Liverpool is going through a transitional period, with new ideas and a different playing philosophy. That takes time. People have to be patient. It's normal for us to be erratic."

Reina says in the same interview that he does not feel like he has made more mistakes than in previous seasons but the stats are there for all to see.

From the summer of 2008 to the end of the 2010-11 season, Reina made just one mistake that lead directly to a goal. That is just once in 114 Premier League games. In his last 54, he has made eight errors which have led to a goal.

This is also Reina's worst season for Liverpool when it comes to the average number of goals conceded in games, which stands at 1.40. It had previously been as low as 0.71 back in the 08/09 season.

It is clear that Liverpool are not as solid as they once were under Rafael Benitez, but the form of Reina is worrying. We all know that goalkeepers can play into their late 30's but is it time Liverpool started looking for a new number one.

There have been suggestions that Reina could possibly return to Barcelona when Victor Valdes leaves and perhaps this would suit both parties. The former Villarreal keeper has been a superb servant to the club but it seems it may be time for a new era.

Manchester United, Arsenal, Tottenham, Manchester City and Newcastle all have first choice keepers aged 25 or under. Perhaps it is time Liverpool follow suit and usher in a new era.

Here's a list of some of the best young goalkeepers currently plying their trade in Europe -

Thibaut Courtois - Atletico Madrid (on-loan from Chelsea)

Marc-Andre ter Stegen - Borussia Monchengladbach

Salvatore Sirigu - Paris Saint-Germain

Francesco Bardi - Inter Milan

Jack Butland - Stoke