Arsenal boss Arsene Wenger has explained why he excluded his leading goal scorer Alexis Sanchez from his starting line-up at Anfield and says he will "stand up" for his decision for the named squad in the 3-1 loss to Liverpool.Wenger included the Chilean among the substitutes at Anfield on Saturday, bringing the former Barcelona forward on at half-time with Arsenal trailing by 2-0.READ MORE: Arsenal fans rage as Sanchez is dropped against LiverpoolThe boss’ decision prompted questions in his post-match press conference and he explained his tactical plan on the club's official website saying: "The thinking was that we had to go more direct and I wanted to play two players who are strong in the air, because we decided to go more direct. After that, to bring on Alexis in the second half. "Of course, I believe in the second half it was easier for the strikers and you could see a different performance from Giroud and Welbeck because we dominated much more of the midfield. Everybody will come to the same conclusion, but I’m strong enough and lucid enough to analyse the impact. And I don’t deny that Alexis is a great player. I bought him and I always played him. This decision was not easy to make, but I have to stand up for it.On Sanchez being frustrated on the bench, Wenger added: "I don’t think there’s any need to go into any individual explanation. What was good in the second half was our collective performance. What was not good in the first half was our collective performance. For me, that’s a much more rational explanation than the rest."You focus on what you want. For every single player, it’s the same. Everybody tells you that you need to buy strikers and then when you have them, everybody asks why you don’t play all of them. It’s impossible." said WengerA solid second-half display was not enough to fix the damage done before the break as Arsenal slipped to defeat at Liverpool. Roberto Firmino scored from close range and Sadio Mane rifled in a second but Arsenal hit back through a brilliantly-worked goal from Danny Welbeck and Sanchez, turning up the heat on Liverpool but it wasn’t enough as the Kops returned the favour on the break to add a third through Georginio Wijnaldum to leapfrog the Gunners in the Premier League.