Aston Villa, Nottingham Forest and Celtic's paths through the Europa League knock-out stage has become clearer after the league phase of the competition drew to a conclusion.

Unai Emery's Aston Villa side secured direct passage to the last-16 of the competition after finishing second in the table, after coming from 2-0 down to beat Salzburg 3-2 on the final matchday.

Nottingham Forest needed an improbable series of results to join the Villains in the top eight, but ultimately missed out despite winning 4-0 against Hungarian champions Ferencvaros.

Forest ultimately finished in 13th place in the table, an outcome which will see Sean Dyche's side seeded in the play-offs - giving them home advantage in the second leg.

There will also be Scottish interest in the play-offs with Celtic going through as an unseeded team after finishing 21st, while Rangers had already been knocked out prior to the final matchday.

Aston Villa and Lyon have been paired as the top two seeds for the remainder of the competition, after the French side topped the table.

The two teams, who are unable to meet until the final, will benefit from having the second leg of all of their knock-out ties at home for the remainder of the competition due to their league phase placing.

Aston Villa and Lyon discovered their potential last-16 opponents, which will come out of two play-off ties.

Emery's side will draw one of Red Star Belgrade, Celta Vigo, PAOK or Lille in the last-16.

Red Star and Celta Vigo will be seeded for their play-off after finishing 15th and 16th respectively, while PAOK and Lille were 17th and 18th.

Nottingham Forest will be drawn against either Fenerbahce or Panathinaikos in their play-off tie, with the two teams unseeded after placing 19th and 20th in the standings.

This could see the return of Rafael Benítez to England, with the former Liverpool, Chelsea, Newcastle and Everton boss currently in charge of Panathinaikos. 

Should Forest come through their play-off tie, they will be drawn against either FC Midtjylland or Real Betis in the last-16.

Forest have already played both teams in the league phase, with both matches coming during Ange Postecoglou's brief tenure as manager.

They drew 2-2 away against Real Betis, before suffering a 3-2 defeat by Midtjylland at home.

Celtic, who finished 21st in the league phase, will be drawn against one of the seeded teams in either Ferencvaros or Stuttgart.

It opens up the prospect of Robbie Keane returning to the club, with the former Celtic striker currently in charge of Ferencvaros.

Celtic would be assured of a match against Portuguese opposition if they reach the last-16, as Martin O'Neill's side would be drawn against one of Braga or Porto.

Looking further ahead in the competition, Aston Villa could find themselves on a collision course with either Freiburg or Roma in the quarter-finals.

The teams finished seventh and eighth respectively in the group stage, with one assured of being placed into Aston Villa’s bracket.

Seeded teams in Nottingham Forest’s section, who would be expected to reach the quarter-finals, would be either Braga or Porto.

The earliest Aston Villa and Nottingham Forest could meet in the competition would be the semi-finals.