MANCHESTER, England, Dec 15 (Reuters) - Manchester United boss Ruben Amorim conceded that repeated lapses in concentration are undermining his team's progress after Monday's chaotic 4-4 draw with Bournemouth at Old Trafford.

Amorim cheered what he thought was the winner when Matheus Cunha scored in the 79th minute for a 4-3 lead. But 19-year-old substitute Eli Junior Kroupi equalised in the 84th minute, the second time in the match United had forfeited the lead.