The Norwegian is pleased with the young Celtic star.
Indeed, the Norwegian feels McGregor has been good for the last two or three months and is now showing the confidence on the pitch that matches his hard work on the training ground.
He told reporters after the 2-1 win:
RD on Callum McGregor: "Been very good in the last 2 or 3 months. Had a break because of other circumstances." (MH)— Celtic Football Club (@celticfc) March 12, 2016
RD: "He is showing a lot of confidence on the pitch, played very well today and he scored again which is important." (MH)— Celtic Football Club (@celticfc) March 12, 2016
RD: "Callum has worked really hard & fantastic at training for a long time. He always does extra and he got his reward for that today." (MH)— Celtic Football Club (@celticfc) March 12, 2016
Leigh Griffiths opened the scoring for the Bhoys at Partick Thistle, with McGregor adding a second nine minutes later.
A consolation goal late on couldn't stop Celtic taking all three points home and they now sit a point above Aberdeen with a game in hand.
Next up for Deila's men is a trip to Kilmarnock, followed by a home game against Hearts.
Celtic have plenty of Scottish Premiership games to contest before they face Rangers in the Scottish Cup semi-final, of course, and Deila, McGregor and co will hope to develop a strong lead in the title race ahead of the chasing Dons.