Ambrose will head home to Nigeria to play for his country in a World Cup qualifier against African rivals Liberia, and the majority of his Hoops team-mates will also be involved in international competition with their respective nations, writes Matthew Lindsay.
Neil Lennon's team produced a flat display as they overcame Hearts 1-0 yesterday in a Clydesdale Bank Premier League clash at Parkhead.
The game came just five days after the Scottish champions beat Spartak Moscow in Russia. However, new recruit Ambrose is confident Celtic can cope with the physical and mental demands of a hectic schedule.
He said: "After the victory in Moscow, the Hearts game was always going to be difficult for us. I had a day off and I tried to recover from the journey.
"We believe in ourselves mentally and as a team and we can withstand the pressure. I can't speak for the rest of the players, but I was okay. But, at the same time, it has not been easy. We have played a lot of games.
"Sometimes when we tried to push, the body would not allow it. That is football. But we managed to hold on to the lead. That was the most important thing for us."