It should be Martin O'Neill's decision whether he stays on as Celtic manager, according to the club's former midfielder Paul Lambert. O'Neill masterminded Celtic's dramatic title triumph - his fourth with the club, 22 years on from his third. The 74-year-old said after the final-day win over Hearts that there had been no talks regarding his future, but Lambert believes it would be "great" for the club if O'Neill were to stay on.