We close our in-depth look at the European Rugby Challenge Cup with a spotlight on Pool 5, which includes three-time winners Harlequins and 1998 runners-up Agen. Agen Ground: Stade Armandie, Agen, France. Challenge Cup record: Of their 15 seasons in European competition, 13 have been in the Challenge Cup, with their most successful campaign being 1997/98, when they reached the final, only to lose 43-5 to French rivals Colomiers. They have qualified for the knockout stages on two other occasions, the last of which was in 2001. Last season: They finished bottom of Pool 3, with their only win of their six games coming in their opening match against Zebre Rugby, whom they beat 45-10. Leadership: Philippe Sella, one of the all-time greats of French rugby, is Agen's general manager. He played 13 years for Agen, before joining Saracens in 1996 and making his only European appearances in their 1997/98 Challenge Cup campaign. The 56-year-old is a member of the World Rugby Hall of Fame, after becoming the first player to appear in 100 Tests, and retired in 1998. Key players: Antoine Miquel and Quentin Béthune have been named as Agen’s co-captains ahead of the new season. The TOP 14 side also include Argentina prop Facundo Bosch and Georgia prop Giorgi Tetrashvili. https://twitter.com/agen_rugby/status/1018909485191061504 Benetton Rugby Ground: Stadio Comunale di Monigo, Treviso, Italy. Challenge Cup record: 2018/19 will be only Benetton Rugby's fourth season in the competition, with their other 20 having been spent in the European Cup. They have never progressed beyond the Pool stage. Last season: They finished at the foot of Pool 5, but their six losses belied their performance levels. Head coach: Former All Blacks full-back Kieran Crowley has been Benetton's head coach since the start of the 2016/17 season. The 56-year-old began his coaching career at New Zealand provincial side Taranaki in 1998 and spent nine years there before being appointed Canada head coach in 2008. Key players: The PRO14 side boast a host of experienced Italian internationals, including flankers Alessandro Zanni and Robert Barbieri, scrum-half Edoardo Gori, and backs Tommaso Allan and Tommaso Benvenuti. https://twitter.com/ERChallengeCup/status/1013676184285179904 Grenoble Ground: Stade des Alpes, Grenoble, France. Challenge Cup record: They have reached the knockout stages once in nine attempts. That came in 2015/16, when they topped Pool 5 after winning five of their six games and then squeezed past Connacht Rugby 33-32 in a dramatic quarter-final. However, they lost 30-6 at Harlequins in the semi-finals. Last season: Grenoble were in France's Rugby Pro D2, so didn't take part in European competition. However, they return to the Challenge Cup in 2018/19 after winning promotion to the TOP 14 via the play-offs Head coach: Stéphane Glas, who played 30 Tests for France and was in the Bourgoin team at centre when they won the first Challenge Cup in 1997, and Dewald Senekal, the South African former Bayonne lock, are Grenoble’s main coaches. Glas looks after the backs, while Senekal coaches the forwards. They are joined by former player Cyril Villain (defence) and Jérôme Vernay (skills). Key players: Goal-kicking full-back Gaëtan Germain, who has amassed 121 points in only 15 European appearances, is likely to be an important figure after his move from Brive. Grenoble will also be expecting big things from their other new signings - Australian utility backs Junior Rasolea and Ben Lucas, Samoa back-row forward Taiasina Tu’ifua and Tonga prop Halani Aulika. https://twitter.com/FCGrugby/status/1018081421087436801 Harlequins Ground: Twickenham Stoop, London, England. Challenge Cup record: Harlequins top the Challenge Cup winners' table, having lifted the trophy three times – in 2001 (the first time they took part), 2004 and 2011. They also reached the final in 2016, when they lost 26-19 to Montpellier. Last season: They were involved in the Champions Cup but won only one of their six Pool matches – a 33-28 thriller against Wasps – and so finished last. Director of rugby: Paul Gustard occupies a club hot seat for the first time after spells as assistant coach, defence coach and forwards coach at Saracens, and then defence coach for England under Eddie Jones. Previously, the 42-year-old played for Leicester Tigers, London Irish and Saracens, and was a member of Leicester's European Cup-winning squad in 2001. Key players: Harlequins have signed Saracens wing Nathan Earle, Bath duo Ben Tapuai and Nick Auterac, and Wasps lock Matt Symons to strengthen their squad. Former Munster man Francis Saili will be eager for greater game time after an injury-hit first season and continue to keep an eye out for promising fly-half Marcus Smith. https://twitter.com/Harlequins/status/1018153160316194816