Copa Del Rey Semi-final 2, 2nd LegTodayBarcelona     vs     Real Madrid    21:55 SS3MADRID - Lionel Messi admits that Barcelona need to raise their level after two below par performances for Tuesday’s El Clasico in the Spanish Cup against a Real Madrid side desperate for a morale boost.Barca made an almost faultless start to the season only dropping points in the league before Christmas with a 2-2 draw with Real Madrid at the Camp Nou, while they also lost against Celtic in the group stage of the Champions League.But now signs of tiredness are beginning to set in."Against Madrid we will have to produce our best football as we will be against a great rival. We need to be at our best in order to get into the final,” said Messi, ahead of the semifinal showdown in the Catalan capital with the scores 1-1 from the first leg at the Bernabeu.The teams then go head-to-head again in the league at the weekend but with Madrid trailing Barca by 16 points in the table there is little more than pride at stake.While they were expected to roll over AC Milan last week in the Champions League, in the end they were unable to break down a well-organised defence as they lacked the movement and the speed of passing.Barca were again lacking potency in attack in the first half against Sevilla at the weekend and went behind before turning the game around in the second half with goals from David Villa and Messi.The Argentine continued his record scoring run in the league to 15 straight games and will be looking to add to his tally against Madrid but there is also plenty of concern about their leaky defence.For Madrid it is the first of two make or break games with the other coming in the Champions League against Manchester United.They struggled once again away to Deportivo la Coruna at the weekend with a weakened side and Cristiano Ronaldo was among those brought on in the second half to turn the game around and give them a 2-1 win.