At the 2010 UK Championship, Allen reached the semi-finals for the first time, where he was beaten 9–5 by eventual champion John Higgins. In the Masters, Allen again reached the semi-finals, and led Marco Fu 4–1 before Fu reeled off five frames in a row to win 6–4. At the 2011 World Championship, Allen entered as the 11th seed and played Matthew Stevens in the first round, recovering from 9–6 down and seeing Stevens miss a pot on the final pink to win the match 10–7, before winning 10–9. In the second round, Allen defeated Barry Hawkins 13–12. He reached the quarter-finals for the second year in a row but lost to Mark Williams 5–13.