The Unai Emery era is in full swing, and after four games, there are enough good things to show us that we are on the right track.Two defeats and two wins only tell half the story of what we have seen unfold on the pitch. We have had electric moments of attack, true fluidity that has seen us rip open our opponents, and create a hatful of chances.What has been abundantly clear though, is our defensive third has struggled to adapt to Emery’s instructions.We were aware that, before a ball had been kicked in anger, that Emery favours a pressing game, and a defence that pushes up to constrict space.Without an effective press, a high line on its own borders on the suicidal, but that is what we have seen, and what has given teams a lifeline that they shouldn’t have had.Without this weakness, our game against Chelsea would have been very different. If West Ham and Cardiff had taken their chances, then they too could’ve been vastly different results.So, how can we avoid this liferaft for opposing teams?There are a few quick fixes that Emery can implement while his new tactics take hold.1)Swap out MustafiIt is clear that from our defence this season, the German has struggled the most. He is an excellent tackler and has a deceptively strong aerial game - but he cannot hold a line to save himself, and under pressure he can crumble. A swap for young Mavropanos or Holding would see a firmer line, and a better chance for the new tactics to blossom quicker as both the youngsters have less years of experience playing other methods to forget. 2) Leno in, Cech outCech is still a great shot stopper, but his footwork is simply not where it needs to be to adapt to the quickfire and short distribution that Emery demands. Leno has that very skill, and we would have an instant benefit of a player who can pass out from the back.3) Torreira to shieldThe Uruguayan was the most effective defensive midfielder in Serie A over the past two seasons. He could come into the side and provide our beleaguered defence another layer of protection they so badly need. He could also be a one man press, which would be a better press than we are mustering right now. These would give us a small but vital boost until Emery has ensured his vision is made tangible on the pitch. The way we have defended in our first four games, all avenues must be explored.