On 17 July 2009, Bertrand joined Reading on a season-long loan. He scored his first professional goal against Derby County on 10 March 2010. He came third in the voting for Reading's player of the season, behind Gylfi Sigurðsson and Jimmy Kébé. On 5 August 2010, Bertrand signed on loan with Championship club Nottingham Forest in an initial six-month deal. He made his debut for Forest as a substitute in a 1–0 away defeat against Burnley. He was a regular for Forest for whom he made a total of 19 appearances. Forest were interested in either extending Bertrand's loan spell for the rest of the season or to sign him permanently but when his loan period expired on 3 January 2011 he returned to his parent club Chelsea. Return to Chelsea 2010–11 season Bertrand made his Premier League debut on 20 April 2011, when he came on as substitute to replace Ashley Cole in a 3–1 win against Birmingham City. Bertrand also made a goal, providing a cross which Florent Malouda headed past Birmingham goalkeeper Ben Foster. On 15 July 2011, Bertrand signed a new four-year contract with Chelsea. He was used as a back-up to Cole by Chelsea manager Carlo Ancelotti, as he remained with Chelsea and left-back Patrick van Aanholt went out on loan. Six years after signing for Chelsea as a schoolboy, Bertrand made his first starting appearance, against Fulham in the League Cup. The match finished in favour of Chelsea, who won on penalties 4–3, as the match ended goalless. 2011–12 season During the 2011–12 season, Bertrand played 90 minutes in Chelsea's 2–0 defeat against Liverpool in the League Cup. He made his first league appearance of the season coming on as a late substitute for Ashley Cole against Everton, the match ended in a 2–0 defeat for Chelsea. Bertrand was handed his first Premier League start against Wigan Athletic on 7 April, in which he produced an outstanding performance, as Chelsea won 2–1 and he was named fan's man of the match. He was again named man of the match in his third start, a 0–0 draw with Arsenal on 21 April. On 5 May, Bertrand won the FA Cup with Chelsea, but he did not appear on the pitch in the win against Liverpool. Bertrand made his European debut in the 2012 UEFA Champions League Final against Bayern Munich on 19 May 2012, playing