Manchester United manager Louis van Gaal thinks Robin van Persie's first half opener was offside as his team beat Leicester 3-1 at home.br br Van Persie and Radamel Falcao put the home side in control, before Leicester's Wes Morgan scored an own goal. A second-half goal from Marcin Wasilewski was bottom-of-the-table Leicester's only reply.br br Colombian international Falcao has been involved in seven goals in nine league starts for Manchester United.