Manchester United manager Louis van Gaal says he is "very frustrated" that his side "gave away two points" in their 1-1 draw against 10-man Aston Villa.br br Radamel Falcao's header cancelled out Christian Benteke's superb opener, but Villa held on for the point despite having Gabriel Agbonlahor sent off for a challenge on Ashley Cole.br br Falcao has scored a goal in each of his last two starts for Manchester United in the Premier League.