Holders Barcelona all but sealed their place in this season's Champions League quarter-finals after beating German opponents Bayer Leverkusen 3-1 away in their Last 16 first leg clash. They could well be joined by Cypriot side APOEL,who came away from French giants Lyon trailing 1-0 yesterday but the fairytale side of this season's competition has every chance of turning the tables in three weeks time. Barca took their time to make their evident superiority tell as the poor run of four away matches without a win appeared to have an effect on the players. However,two goals from Chilean star Alexis Sanchez,the first one set up by three-time world player of the year Lionel Messi,who also grabbed the third which was the best of the match. Michal Kadlec had briefly given the hosts hope of earning a notable result,but Leverkusen were their own worst enemies as they missed several chances of their own to leave them with a daunting task in Barcelona. Barcelona coach Pep Guardiola,who faces an almost impossible ask in retaining the domestic league title as bitter rivals Real Madrid have a 10 point lead,admitted his side had taken time to assert their authority. "I think the second half was good,we used the space better after we took the lead," said Guardiola. "We tried to improve our game,we had a few chances in the first half,but perhaps the final pass was missing. "But we were playing away and we came into the game after the break." His Leverkusen counterpart Robin Dutt also thought that his team had produced their best football in the second-half,but not good enough to end a poor run which has seen them win just once in eight matches.