Answer
Neil Lennon was Celtic's manager when James Forrest made his first-team debut in 2010. Lennon, a former Celtic player himself, was appointed manager in 2010 and led the team to three consecutive Scottish Premiership titles, as well as two Scottish Cups and a Scottish League Cup. Forrest, a winger, has since become a key player for Celtic, making over 400 appearances and winning numerous trophies.