Celtic manager Neil Lennon praised the strength of his players, some of whom have featured in 35 games already, after they extended their unbeaten start to the Scottish Premiership season to 17 games.
Dutch defender Virgil van Dijk got the only goal of the game in the fifth minute with a superb finish following a mazy run which started just inside his own half as the Hoops secured a 1-0 win over St Johnstone at McDiarmid Park.
It has been a long season for the Glasgow giants, who started their campaign in mid-July as they faced three qualifying rounds on their way to making the group stages of the Champions League.
Despite this, the Glasgow giants have now built up an ominous 11-point lead at the top of the Scottish Premiership table and Lennon said his side were working hard to preserve their unbeaten status in the league.
"Our performances have been fantastic. There are only a few clubs now in Europe unbeaten and we want to preserve that for as long as we can," the Celtic manager said.
"That takes a lot of physical and mental strength and they have shown that in abundance.
"Some of our players have played 35 games already. That`s a season for some people and we`re not even out of December yet.
"We would have dropped points this time last year. There is more of a will to win about this year.
"At times it`s not pretty but you can`t always play silky football the way you`d like.
"You have to earn the right to play and sometimes you have to dig out a few results. But I always felt we were in control of the game but for that 10 or 15 minutes in the second half."
St Johnstone had threatened to strike first at McDiarmid Park as Stevie May chased down a long ball out of defence but van Dijk raced back to nick the ball off the striker`s foot and put it out for a corner.
The Dutch defender then showed off his skills at the other end of the park as he put Celtic ahead with a superb solo goal.
Van Dijk picked up the ball just inside his own half and after a jinking run past a couple of defenders he arrowed a low shot past goalkeeper Alan Mannus.
Van Dijk has been a stand-out in a Celtic defence that has kept five straight clean sheets in the league and have conceded just 12 all season and Lennon was full of praise for the former FC Groningen player.
"He`s a smashing player and he`s only going to get better as he`s only 22," the Celtic manager said.
"Defensively he`s been fantastic for us. He`s a technically gifted footballer and he`s a great athlete. His all-round game is very good at the moment."