Arsenal captain Per Mertesacker has revealed what he and Rob Holding did to upset Chelsea striker Diego Costa during Saturday's FA Cup final showdown at Wembley.Mertesacker who was making his first start of the season led Arsenal as they pulled off an unlikely victory over Chelsea in the FA Cup final on Saturday to salvage something from a miserable season that saw them being dumped out of the Champions League place next season.They were dumped out of the Champions League at the last-16 stage once again after losing by an embarrassing aggregate score of 10-2. They also fell away from title contention just after Christmas and finished 18 points behind champions Chelsea. Worse still, they failed to finish in the top four for the first time in 20 years.That meant the FA Cup presented their only chance of success this season - much like the last few years - and they seized the opportunity against a much-favoured Chelsea side. But keeping Diego Costa quiet was always going to be a key feature of any Arsenal victory and there is no doubt Per Mertesacker and Rob Holding did a tremendous job of keeping him at bay. "We went to work on Diego Costa. Rob was giving him a really hard time. I kept patting him on the back, being friendly, while Rob kept on talking to him. A good double act. It was very exciting to see how quickly things can turn. What was really important was that we kept on running with Costa, to make sure those long balls didn’t get to him.“We were prepared for that. Especially when Fabregas came on, we were ready to run back to cut out those long balls over the top that he plays.“You have to say it couldn’t have gone much better for us. The team’s performance was incredible. I don’t know how many would have expected that.” said Mertesacker on Givemesports.Not many fans really gave Arsenal a prayer against such a well-oiled Chelsea unit, but Arsene Wenger's men managed to get the job done and although any cup win is good, there is only so long that will placate a frustrated Arsenal fan base.Now, the manager's future needs to be sorted out in order for the Gunners to move forward with their summer business and prepare for next season.