There is a belief that Celtic stand on the brink of an era of domination of the domestic game. The problems at Rangers are colossal and their top players will not wait around for their resolution.
The focus for the Celtic board, management and supporters will now be how to progress in Europe. Peter Lawwell, the club's chief executive, has spoken about the addition of a couple of players before the Champions League campaign, but the Parkhead club will also sell personnel.
There will be sober thinking after the justifiable excesses of a championship celebration. The Celtic philosophy now is to invest in the academy and in the scouting operation. The best fruits of this combined operation will be sold on to fund the running of the club.
It is perhaps relevant, then, to consider who will be going before ruminating on any future destination for the club. It is likely Celtic will sell one, perhaps two players in the summer. Gary Hooper, despite his two goals on Sunday, already looks like a player with another club. Lennon, too, is well-staffed in midfield and could let a player go in this area. Ki Sung-Yueng is the obvious candidate as he has already attracted interest and is not a certain starter in Lennon's best team. Kris Commons may also be on his way. James Forrest, in contrast, will stay in the short-term and move in the long-term.
Decisions will have to be made, too, on players such as Paddy McCourt and the nine of his team-mates on loan at other clubs. Room has to be made to give academy candidates an opportunity. Dylan McGeouch and Marcus Fraser have already shown they are ready to take that chance.
Crucially, the scouting operation and Lennon's decisions on their advice have been outstanding. Celtic have a young side with potential. Biram Kayal, Ki, Victor Wanyama, Joe Ledley, Adam Matthews, Thomas Rogne and Emilio Izaguirre have all made a contribution to the team after being identified and bought at little or no cost. With Forrest blossoming, Charlie Mulgrew developing and Scott Brown showing signs of the talent that attracted a £4m fee, Lawwell's assertion that the club now has a "solid foundation" is valid.
But how will Celtic fare in Europe? The Champions League is an unforgiving arena for inexperienced sides but the Europa League campaign this season gave Lennon cause for hope. Outplayed by Sion, Celtic took their reprieve and learned from the competition even if they did not prosper. Lennon and his players were tested by the demands of Udinese and Atletico Madrid, in particular. They were not dismayed even if they did not make it into the knockout phase.
The Celtic manager has shown he is energised by the demands of the top-level. He is a deep thinker of the game and will want to take his ideas into the Champions League group stages. He will not have the ammunition afforded to Martin O'Neil or even Gordon Strachan but he has shown he can both identify and improve players and that is the ultimate test for any manager.
Mulgrew, once considered not up to standard at Celtic, has become the player-of-the-season, drawing praise from Tommy Gemmell, who knows something about left-back play. "The lad has had a tremendous season and showed a lot of courage," said the Lisbon Lion of Mulgrew. "It was obvious he was desperate to get a hat trick against Killie. I like his style – a left-back trying to get three goals without the help of a deadball effort. He could continue doing it in Europe, too."
This theme was continued by Rogne. "I feel very good at Celtic and my agent is currently in talks with the club about a new contract," revealed the 21-year-old Norwegian defender. "I hope that resolves itself very soon because I want to stay here. And I really believe we can make an impact in Europe next season too."
Both Mulgrew and Rogne sum up the potential and the difficulties at Celtic. Both have improved and can improve further but both have shown fallibility at crucial moments in matches over the past two seasons. Celtic have been accused of lacking "bottle" yet they are a team who went on a long, unbroken run, defeating Rangers to take a lead in the Clydesdale Bank Premier League they never relinquished. Of course, they have been beaten by both Rangers in the league and Kilmarnock in the Scottish Communities League Cup final, but the major missing element on both occasions was a lack of experience within the Celtic ranks.
It will be fascinating to see who Lennon targets to bring to Parkhead over the summer. His first inquiries when becoming manager at Celtic concerned the possibility of attracting David James and Sol Campbell who were 40 and 35 respectively at the time. Lennon has won a league with young Bhoys but knows he needs older heads for Europe.