Nir Bitton believes he is playing his best football at Celtic since joining the Scottish champions in 2013 from Ashdod.
The Israeli midfielder was a bit-part player under Ronny Delia during the opening months of the season.
But he admits that a heart-to-heart with the manager has brought out the best in him.
He said: "I played a lot in my first season when I was settling in and then came a new manager last summer and everything changed.
"The turning point came in November. The boss told me exactly what I was not doing well and what he expected.
"Some players feel hurt by such criticism, but I took encouragement and since then I’ve played 90 minutes in every game."
Della sang Bitton’s praises after the 3-3 draw against Inter Milan in the Europa League. He said: “We have only seen the beginning of him and he can only get better."
Bitton, 23, is eager to move south of the border one day. “Every player wants to get to the top, but it’s too early to talk about the Premier League,” he said. “I’m concentrating on keeping my place in the Celtic team."