At the start of the 2010–11 season, he was a regular in the first team. However, when Alan Pardew lost his job just days after a 4–0 win away to Bristol Rovers, Southampton hired Nigel Adkins as manager. Under Adkins, he stayed in the first team, but found himself under increasing pressure from Alex Oxlade-Chamberlain for his place. Eventually Adkins lost patience with Puncheon's erratic performances, and dropped him to the bench in favour of 17-year-old Chamberlain, who was later sold to Arsenal for a reported £15m. On 16 November 2010, Puncheon moved on an emergency loan deal to Millwall. He scored his first goal on his first game for Millwall in their 1–0 victory over Middlesbrough. On 1 January 2011, Puncheon scored a hat-trick in the 3–0 victory over Crystal Palace.