Chelsea having great season, insists Rafael Benítez after beating Manchester United in FA Cup My priority is the top four and trying to win the next game, in the Europa League. The priority for us is to finish in the top four, we know that, but at a top side you have to win every competition. Benítez confirmed that Gary Cahill would be missing for up to three weeks with a knee injury while Ashley Cole limped off clutching a hamstring and is expected to be out for at least two weeks. With so many important matches looming, Benítez knows that he faces a delicate balancing act with his squad. "I don't think our squad is too big but, if we don't have injuries, we'll be fine - we have to manage the players we have," he said. Ashley is out for at least two weeks, so, for us, that means 20 games. Benítez also defended the decision to start on Monday with Cole, David Luiz, Eden Hazard, Juan Mata, Ramires and Demba Ba after they had all either been rested, unavailable or initially on the bench against Southampton on Saturday. "Before the international break we played against United, Steaua Bucharest and West Ham," he said. We were the best in the world. We lost against Southampton and we're the worst in the world. You have to have balance. We only had 48 hours between games and don't have a long squad [in depth]. We had to approach Southampton in a different way because of the players we had on the pitch. These were skilful players with talent and ability. You cannot kill players by playing them two games in a row in that time. Sometimes, for you, a strong team is something different to what I pick. Benítez also praised the contributions of both Ba and Petr Cech for respectively producing a match-winning goal and save. "It was important for everyone here," he said. A cup competition you have to win. If not, you're out. We have scored a lot of goals, but this was one of the best. Really important, very good technique, very difficult. Of Cech, he added: "It was important. It was a great save. Chelsea are now only two games away from winning a fifth FA Cup in seven years. "We love Wembley, we respect the FA Cup as a whole and we always want to win," said Cech. For my save it was a great ball into the box and I just went as fast as I could and let my left arm do the job and luckily I was able to reach it. Ba added: "I have scored similar goals like I did today against Manchester United for Newcastle. It was a brilliant pass for my goal and the win is great for confidence for the rest of the season.