See main article: 2016–17 European Rugby Challenge Cup. The 2016–17 European Rugby Challenge Cup pool stage was the first stage of competition in the third season of the European Rugby Challenge Cup.
It involved 20 teams competing, across 5 pools of 4 teams, for 8 quarter-final places – awarded to the 5 pool winners and the 3 top-ranked pool runners-up.
The pool stage began on 13 October 2016 and was completed on the weekend of 19–22 January 2017.
The 20 competing teams were seeded and split into four tiers; seeding was based on performance in their respective domestic leagues. Where promotion and relegation is in effect in a league, the promoted team was seeded last, or (if multiple teams are promoted) by performance in the lower tier.[1]
| width=5% | Rank | width=19% | Top 14 | width=19% | Premiership | width=19% | Pro 12 | width=19% | Qualifying Competition |
|---|---|---|---|---|---|---|---|---|---|
| 1 |  Enisey-STM | ||||||||
| 2 | Timișoara Saracens | ||||||||
| 3 | |||||||||
| 4 | |||||||||
| 5 | |||||||||
| 6 | |||||||||
| 7 |
Teams was taken from a league in order of rank and put into a tier. A draw was used to allocate two second seeds to Tier 1; the remaining team went into Tier 2. This allocation indirectly determined which fourth-seeded team entered Tier 2, while the others entered Tier 3.
Given the nature of the Qualifying Competition, a competition including developing rugby nations and Italian clubs not competing in the Pro12, Rugby Europe 1 and Rugby Europe 2 were automatically included in Tier 4, despite officially being ranked 1/2 from that competition.
The brackets show each team's seeding and their league (for example, 1 Top 14 indicates the team was seeded 1st from the Top 14).
| width=5% | Tier 1 | width=19% | Harlequins (1 AP) | width=19% | Cardiff Blues (1 Pro12) | width=19% |  Brive (1 Top 14) | width=19% | Ospreys (2 Pro12) | width=19% | La Rochelle (2 Top 14) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| width=5% | Tier 2 | width=19% | Gloucester (2 AP) | width=19% | Bath (3 AP) | width=19% | Edinburgh (3 Pro12) | width=19% | Grenoble (3 Top 14) | width=19% | Worcester Warriors (4 AP) | |
| width=5% | Tier 3 | width=19% | Pau (4 Top 14) | width=19% | Newport Gwent Dragons (4 Pro12) | width=19% | Newcastle Falcons (5 AP) | width=19% |  Treviso (5 Pro12) | width=19% | Stade Français (5 Top 14) | |
| width=5% | Tier 4 | width=19% | Bristol (6 AP) | width=19% | Lyon (6 Top 14) | width=19% | Bayonne (7 Top 14) | width=19% | Enisey-STM (QC 1) | width=19% | Timișoara Saracens (QC 2) |
The following restrictions apply to the draw:
The draw took place on 29 June 2016 in Neuchâtel, Switzerland.
During the pool stage, the teams played the 3 other teams in their pool twice, both at home and away,[2] Based on the result of the match, teams receive:[3]
Following the pool stage, the five winners from each group progressed to the quarter-finals, along with the three best pool runners-up from the competition. In the event of a tie between two or more teams from the same pool, the following criteria were used as tie-breakers:[3]
If this did not separate teams, and/or the tie related to teams that did not play each other (i.e., in different pools), the following tie breakers were used:
| Winner of each pool, advance to quarter-finals. | ||
| Three highest-scoring second-place teams advance to quarter-finals. | ||
| Cannot advance to the quarter-finals. |
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Due to a frozen pitch at the main ground at the Stadio Comunale di Monigo complex, kick off was delayed by 2 hours and moved to a nearby training ground.[4] ----
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----Due to a frozen pitch on the 8 December, the game was postponed to the following day.----
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Following this win, Ospreys were the first-ever team in the history of either European rugby competition to get 30 match points out of 30 at the pool stage.
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----Due to cancelling the game, Timișoara Saracens were fined €30,000. Stade Français were awarded 5 match points in lieu of playing.[5] ----