What now for O'Riley's life after Celtic?

Speculation about Matt O'Riley's future had been a daily constant in Scotland's media long before confirmation of his transfer to Brighton & Hove Albion from Celtic for what is likely to be a Scottish record fee.

Indeed, since Atletico Madrid had an approach rejected in January, it has seemed only a matter of time before somebody matched Celtic's valuation for the elegantly influential 23-year-old.

This summer, it had been Atalanta who were most strongly linked with the London-born Denmark international - until Brighton made the decisive move.

So what are the Premier League club getting and how might his departure affect Celtic?

Life of O'Riley so far

Matt O'Riley (left) last played in English football with MK Dons

A native of Hounslow, O'Riley joined Fulham's academy at the age of eight, graduating to a first-team debut as a 16-year-old in an EFL Cup win away to Wycombe Wanderers.

However, having made just five appearances and only one in the league as a substitute, in the three years thereafter, the England youth international rejected the offer of a new contract and joined MK Dons in League One.

With 10 goals in 54 appearances, nearly all of them starts, O'Riley had already shown his goal threat from midfield.

Those performances persuaded Celtic to shell out a reported £1.5m in January 2022 to match his release clause.

Eligible to represent Denmark and Norway via his mother's side of the family, it only took three months starring in the Premiership for O'Riley to be called up to Denmark Under-21s.

Four years on and he has accumulated three league winners' medals, two for the Scottish Cup and one for the League Cup as well as vital experience on the European club stage.

What does O'Riley exit mean for Celtic?

O'Riley's statistics are impressive.

Since arriving at Celtic, he has provided more assists than anyone in the Scottish Premiership, his 29 being six more than Rangers captain James Tavernier.

O'Riley ranks third when combining goals and assists, his 54 involvements only two behind Heart of Midlothian striker Lawrence Shankland and seven adrift of Tavernier, Rangers' regular penalty taker.

O'Riley (217) is second only to Tavernier (275) and well ahead of the next best, Kilmarnock winger Danny Armstrong (173) in terms of chances created - and only 10 behind the Rangers captain when considering only those from open play.

As for touches in the box, O'Riley outshines any Premiership player, his 555 being more than Shankland's 498 and well ahead of team-mate Daizen Maeda and recent Girona capture from Aberdeen, Bojan Miovski.

O'Riley is also fourth best for successful crosses behind Tavernier, Armstrong and former Rangers left-back Borna Barisic - and his 25 goals over the past two years is only bettered by four strikers and Tavernier.

Those steadily improving numbers mean O'Riley had possibly now overtaken captain Callum McGregor and Japan's Reo Hatate in terms of importance to Celtic.

The trio have been central to a scintillating start to this season for Brendan Rodgers' side.

Acknowledging their role last week, the manager said: "In my history as a coach, the dynamic midfield three is always important.

"It's never about one player, it's always about the three. And I think that it was probably only into the latter stages of last season that those three came together.

"And I think you've seen the flow and the dynamism and how it all makes the team function."

Rodgers had repeatedly said he did not want to lose "a brilliant player" with "phenomenal mentality", saying he already needed an extra central midfielder to bolster his squad for the Champions League even if O'Riley stayed.

Soundings from Celtic suggested it would take an offer north of the club's reported £25m record sales for both Kieran Tierney and Jota to prise O'Riley away.

After McGregor and Hatate both scored in O'Riley's absence in Sunday's 3-0 win over St Mirren, Rodgers expressed his frustration at the slow wheels of Celtic recruitment.

However, he vowed that the squad would be improved before the transfer window closed and that speed will only surely hasten armed with the O'Riley money.

What does O'Riley arrival mean for Brighton?

Matt O'Riley will hope a move will bring more Denmark caps

O'Riley will have been disappointed to have missed out on the Denmark squad for this summer's Euro 2024 finals.

After handing him a start in their 2-0 qualifying defeat by Northern Ireland in Belfast, then head coach Kasper Hjulmand explained in March he thought O'Riley had six better midfielders in front of him.

O'Riley will perhaps think he has a better chance of adding to his two caps now that former Celtic midfielder Morten Wieghorst has been appointed caretaker boss, but playing regularly in one of the top leagues will help his cause.

Europa League winners Atalanta had appeared to be favourites for his signature, but after reportedly failing with a series of bids, the Serie A club last week signed Serbia international Lazar Samardzic from Udinese.

Unlike the Italians - and Celtic - Brighton cannot offer European football this season, but they have been investing heavily this summer under new head coach Fabian Hurzeler.

Pascal Gross has joined Borussia Dortmund and Adam Lallana moved to Southampton, while defensive midfielder Mats Wieffer has arrived from Feyenoord and Turkey international Ferdi Kadioglu is also on the verge of a move from Fenerbahce.

Hurzeler, who led St Pauli to promotion to the Budesliga before becoming the youngest permanent head coach in Premier League history, sees the latest arrival as a bit a "specialist".

"He is very good at occupying and attacking the right space," he told his club website. "He likes making deep runs and knows when to attack at the right time.

"He enjoys getting forward and attacking the opponent's penalty area, but he also has a good defensive instinct. That balance makes him special."

O'Riley has a languid running style that is somewhat deceiving given his qualities as a constantly involved, pivotal all-rounder.

A somewhat different player to the more defensive Billy Gilmour, who impressed Hurzeler against Manchester United on Saturday, but the latest arrival will further fuel speculation about the Scotland midfielder's future amid reported interest from Napoli.