Kelly, bidding to secure a regular place in Steven Gerrard’s first team squad after spending the previous two campaigns on loan at Ayr United and Ross County, was among a raft of second half changes for Rangers who grabbed the only goal of the game through Cedric Itten with seven minutes remaining.
Along with more experienced players used by Rangers, who made 10 changes at the interval, Kelly helped increase the tempo and fluency of his team’s display.
“Stephen has progressed really well,” said McAllister. “He has had a couple of good loans and went out and impressed with every team that he has gone to. I think he warranted that tonight in amongst some senior players and top international footballers. He was very competent.
“The second half, we played more senior players on the pitch and you could see the composure and the quality. Looking at Steven Davis again, outstanding and I thought he was the pick of the game tonight. Stephen Kelly also did fantastically well but overall we are delighted for all the players and they are looking pretty sharp.
“We said Thistle would give us a good test and it was. It was a great exercise tonight with 20 outfield players getting 45 minutes, which is getting minutes into their legs.”
McAllister was also pleased to see goalkeeper Robbie McCrorie, the only Rangers player to play the full 90 minutes, keep a clean sheet. The 23-year-old spent last season on loan at Livingston.
“When you look at Robby now, he really has matured,” McAllister told Rangers TV. “I have noticed that around the training ground. He has become more of a man, taking more responsibility and ownership of his back four. He had a great save from the big lad (Brian) Graham to tip it over the bar and he had a good night.”
Rangers are next in action on Saturday when they travel to face English League Two side Tranmere Rovers at Prenton Park.