Mahmood, a former Pakistan cricketer, on Saturday took three wickets and scored 18 runs in his side's close seven-run win over Chennai Super Kings.
"He has been impressive with his whole approach and the attitude. He is level-headed and wants to share it with others on the field as well as off it. He certainly has made a nice, little impact for us," Gilchrist, who is still out of action due to injury, said.
The Australian though rued that Mahmood could not make the most of the blistering start to his innings, which had two sixes.
"It's a shame that he couldn't convert that into a big knock, but these are the sort of small moments of impact. It definitely gave us the impetus, and he has been dying to get into the top order," he said.
Gilchrist also patted spinner Piyush Chawla for his good show on Saturday, specially after a shattering experience in the last match against Mumbai Indians when he leaked 27 runs in one over.
"He bowled a match-winning spell and it shows his courage and character to bowl so outstandingly after the Mumbai match."
Praising opener Mandeep Singh, who scored 56 off 50 balls on Saturday, Gilchrist said," He is not the guy to get 60 off 30 balls, but he allows us to compile big scores as he did today. We had a good start, but our execution with the bat was slack at the back-end on the match."
The skipper was also delighted with his side's good comeback in the tournament after a sluggish start.
"It's (points table) is quite congested but we are happy that we could hold it together here. They needed 32 off 12 balls, the same target Mumbai also required, but today they ensured that they don't slip through."
Talking about David Hussey's captaincy, he said," He marshaled his troops well, and even on the other night (when they lost to Mumbai) I don't think he erred. But bowling spinners in the last three overs is a big risk unless you are playing on an extremely spinner-friendly wicket."
Gilchrist also felt that paceman Ryan Harris' comeback in the side will only strengthen the bowling.
"He's an aggressive bowler and he is a great value addition by way of his character in the dress room. He's a bit like what CSK feel when Mike Hussey return."
Photos: Katrina Kaif, Shamita Shetty at Mumbai airport
Photos: Varun Dhawan, Alia Bhatt promote 'Badri...' on 'Dil Hai Hindustani'
In pictures: 15 facts about kissing that will surprise you
Photos: Shahid Kapoor and Mira Rajput at cafe in Bandra
Photos: Deepika Padukone, Neha Dhupia and Soha Ali Khan at event