The first round of games in the group phase of this season’s Europe League get under way on Thursday as 23 clubs make their first appearance at this stage of the competition – including Tromso - with some having particularly tough opening fixtures.
The Norwegian side qualified after Besiktas were thrown out for match-fixing and travel to England to meet Andre Villas-Boas' side for the first time.
Tottenham have started the Premier League season with three wins from four games and, despite losing Gareth Bale to Real Madrid, have signed seven new players including Christian Eriksen and Roberto Soldado.
Another debutant in the group stage are Swansea City, who head to Valencia.
Michael Laudrup's men made short work of Petrolul Ploiesti in the qualifying play-off, but know they will have to raise their game at the Mestalla.
Valencia opened their La Liga campaign with a win on the opening day before slipping to three consecutive defeats, conceding three goals during each loss.
That will give hope to Swansea, who have added Jonjo Shelvey and Wilfried Bony to their ranks during the close-season to support last season's top scorer Michu.
The surprise package in the Portuguese Primeira Liga last season – Pacos de Ferreira – travel to Florence to face Vincenzo Montella's confident Fiorentina.
After losing in the play-off rounds for the UEFA Champions League, Pacos take their place in the Europa League for the first time.
They meet a Fiorentina side who are unbeaten in Serie A this season and have strengthened their squad with the arrival of Mario Gomez, Joaquin and Josip Ilicic.
Sevilla - who won this competition in 2006 and 2007 – face Estoril in their opening Group H match.
Unai Emery's side came close to earning a 2-2 draw at Barcelona on Saturday before conceding a 94th-minute goal, but their Camp Nou performance will give them plenty of competition heading into Thursday's game.
Emery will be wary of Estoril midfielder Evandro Goebel, who has scored four goals in the opening four games of the league campaign.
New-look Anzhi Makhachkala travel to Moldova to face Sheriff hoping they are not hampered by the loss of many of their big-name players.
The likes of Willian, Samuel Eto'o and Lassana Diarra have all left the club as Anzhi look to rely on young, homegrown players as opposed to expensive foreign imports.
There are 24 Europa League clashes in total due to take place on Thursday as the likes of Lyon, PSV and Lazio join at this stage of the competition and face Real Betis, Ludogorets, Legia Warsaw respectively.
