LONDON (REUTERS) - Much of Liverpool's early-season optimism drained away as familiar weaknesses and a lack of squad depth were exposed in a 1-0 defeat to Southampton on Saturday.

The club ended the day level on points with Chelsea at the top of the Premier League table, but Dejan Lovren's simple set-piece goal and Liverpool's failure to land a telling blow of their own told a different story.

It is a familiar tale for Liverpool fans who over recent years have become used to seeing their team fritter away periods of good form by flattering to deceive against a team they were expected to beat.

Premature talk of a potential title challenge was silenced and replaced with commonly heard questions about whether they have a squad capable of sustaining a charge for a top-four spot and Champions League qualification.

"We've been unfortunate to lose a number of injured players all at the same time," manager Brendan Rodgers told reporters in mitigation.

"But we have what we have and the players have been brilliant. Today hurts, because we haven't tasted defeat for such a long time." This was Liverpool's first loss since they were outplayed by the same opponents in March last season, but in the 13 intervening league matches they have been held to home draws by Reading and West Ham United, two games an established top four side would expect to win.

Liverpool's pedestrian approach play on Saturday highlighted the pivotal importance of creative lynchpin Philippe Coutinho who has been ruled out for six weeks with a shoulder injury he suffered against Swansea City on Monday.

His exit in that match coincided with Liverpool ceding possession and territory and ultimately conceding a second-half equaliser to draw 2-2, while on Saturday it enabled Southampton to starve in-form striker Daniel Sturridge of possession.

Liverpool's attacking ambitions were also frustrated by having to field four central defenders across their backline, an unfortunate consequence of mounting injury and fitness problems.

"It was really what we had available," Rodgers added. "We've got Glen Johnson out injured and Martin Kelly's only returning - he's had a few games, but he's still trying to work up his fitness having been out for a year.

"Jose Enrique is one we've got to keep an eye on his knee.

He's got an issue with his knee and if there is an overload on that, it could maybe put him out longer term. We've got (Aly) Cissokho out already." One positive to emerge out of defeat was that the fixture heralded the end of striker Luis Suarez's 10-match ban for biting Chelsea's Branislav Ivanovic last season.

The Uruguay international's goals have frequently dug Liverpool out difficult situations in the past and his ability to create something from nothing will be invaluable going forward.

"I think that's a positive from today; the fact that he is back now, the ban has finished and he's available from next week," said Rodgers.

"Sometimes in these games it's players like him (Suarez), who can make the difference. It's going to be great to have him back."