Manager Neil Lennon was delighted to see Celtic follow their Champions League success in Moscow with a narrow win at home to Hearts.
Georgios Samaras fired his second winner this week to send Celtic back to the top of the Scottish Premier League.
"You could see the fatigue kicking in after an hour," explained Lennon on BBC Radio Scotland. "There were players running almost on empty.
"Champions League games are very demanding, so I am thrilled."
Samaras drilled home the game's only goal on 34 minutes and Celtic comfortably held off Hearts, even if their performance lacked the sparkle of their maiden Champions League away win against Spartak.
"It's been a tough week but very satisfying and rewarding," said Lennon, who brought in James Forrest to allow captain Scott Brown time off to recover from a troublesome hip injury.
"Maybe with hindsight we could have freshened things up more, but we wanted to keep that momentum going.
"I thought we played okay, we created good chances. We just didn't put Hearts away. We hit the post and flashed a few across the goal.
"It was probably a bit of muscle heaviness that prevented us from winning the game more comfortably.
"But it was a good day's work. Hearts are a good team and they had a good urgency about them.
"I can't speak highly enough of the player's efforts this week and to top it off with a win and a clean sheet is brilliant."
Lennon, who spoke glowingly of his relationship with the club's majority shareholder, Dermot Desmond, was given another boost this week when Forrest, Charlie Mulgrew and Adam Matthews agreed new contracts.
The manager hopes to have more good news in that department soon.
"We're still in talks with Victor [Wanyama] and Gary [Hooper]," he said. "We'll hopefully get over the line shortly with those two."
On the subject of his own contract, Lennon continued: "I'm on a rolling deal and things are going well.
"If the opportunity comes round, we'll sit down and discuss it, but there are more important issues to take care of at the minute. That's certainly the players."
Lennon, who first took over on a temporary basis in March 2010, also revealed that he thinks he is growing into his role in the dugout.
"I'm more comfortable in the job, but that comes with experience and winning the league was a huge psychological step for me," he continued.
"People looking in say it's a two-horse race and I don't like coming second in anything.
"Qualifying for the Champions League gave me a real shot in the arm. I put so much pressure on myself to get the club moving forward.
"It gives us a mark of respect around Europe and slowly but surely we are getting there."