Celtic moved swiftly to beat another midnight deadline last night when Gary Mackay-Steven and Stuart Armstrong were registered with Uefa for their Europa League squad list.

A Hoops spokesman confirmed that the registration of both players - as well as on-loan hitman John Guidetti, who had been signed too late at the start of the season to make the original list - had gone through in time.

It means all three players are eligible to feature against Roberto Mancini's struggling Inter Milan in the last-32 double-header later this month.

The news is a significant boost for Ronny Deila, who will see Armstrong and Mackay-Steven cup-tied for the QTS League Cup final against Dundee United on March 15 as well as Saturday's William Hill Scottish Cup-tie at Dens Park.

Scottish Cup rules forbid players playing in the competition for two clubs, meaning that even if Celtic progress at Dundee's expense, the former Tannnadice duo will have to sit out.

And Armstrong has admitted that the lure of playing European football was a significant selling point when Celtic came calling.

"What is not to like about Celtic? You grow up watching European football and you have a chance to be a part of that which is pretty special," he enthused.

"That was a big factor. You grow up watching big European nights on TV and think what it would be like to be involved with it. It is very exciting now to see that chance there, to be a part of it. I just can't wait to get in and get started now."

While the players will be entitled to be part of Deila's European plans, their first goal will be to get themselves into the team.

"The competition for places is a challenge I think that you have to embrace," said Armstrong.

"It's such a big club and you have to be up for the challenge, trying as hard as I can to show my ability.

"Celtic is a much bigger club than I am used to and with that comes a greater responsibility. But I'll look forward to embracing that."

Meanwhile, Mackay-Steven has appealed to the Dundee United fans to appreciate why the players made the move to Glasgow.

Both are likely to get a warm reception upon their return to Tannadice with Celtic, but Mackay-Steven hopes it's not too brutal.

"I am very grateful for the way the fans and the staff treated me throughout my four years there," he said. " I had nothing but fabulous support. I think it will be a little bit different when I go back to play there and I am not in tangerine, but I hope they will see the bigger picture.

"We still have a part of Dundee United with us, but we wanted to further our careers."