Looking at the goal again, shouldn't Skrtel move across and plug the gap left after Lovren picks up Tadic? He points Tadic out and sees the danger presumably, but is still rooted to his spot with no one to mark.
Yes. I rewatched the match again and paid close attention to defensive spacing of the back four. I noticed that this occurred several times, particularly as a consequence of Skrtel being static.
Southampton's equaliser has already been discussed and is simple to analyse in my view. Lucas should have tracked the run and Skrtel should have been in a better covering position.
Apart from that occasion I spotted two fundamental issues which occurred more than once:
The spacing between the back four as mentioned. If I knew how to post screen shots, I would. Perhaps someone else could do the hard work. Many times Manquillo and Skrtel were within three yards of each other with at least double the distance between Skrtel and Lovren. Ideally the back four should be spaced evenly depending upon the position of the attacking threat.
The other noticeable issue was Gerrards habit of standing still in defence. At least three times I noticed that he allowed the opposition to drift by him while watching the ball. The most apparent occurrence was when Clyne nearly scored a second. Three Southampton players drifted past Gerrard into the box to create an overload. Gerrard did not move from the D. It would be great if someone could post the highlight. I believe that this is simply a lack of defensive instinct on his part which will be very difficult to coach into him now. For example, a player like Mascherano would instinctively sense that a dangerous situation was developing and plug the gap.
I do hope that the spacing issues are addressed by Rodgers as they seem to be easily fixed. While I am not a coach, there must be a number of drills to have the appropriate movements ingrained. One thinks back to Sacchi's Milan as an example.