Premiership leaders Saracens find themselves behind the eight ball as they face a must-win European clash in Toulouse on Sunday.
With the sides level at the top of Pool 3 and with Toulouse a safe bet to get a full house of points against Zebre next week, Sarries must win at a sold-out Stade Ernest Wallon or risk missing out on a place in the quarter-finals.
Four-time Heineken champions Toulouse have a formidable home record, with last month's shock defeat to Connacht the only blemish on an otherwise perfect record this season.
One should not read too much into that result. Toulouse were simply caught out for arrogantly underestimating their opposition and were forced to sheepishly admit as much in the aftermath. Sarries will pay far more attention to the five-try thrashing dished out in Galway a week later.
Indeed, Saracens will have to produce something special if they are to exact revenge for the 17-16 loss at Wembley in October.
"Toulouse beat us in London, so we are behind the black ball a little bit, but we go into the game in good spirits, in good form as well," said Saracens director of rugby Mark McCall earlier this week.
"But we have got to get a lot of things right when we go over there to make sure we win."
Toulouse boss Guy Novés - the master of talking up the opposition - called Sarries the "All Blacks of Europe" . There's no small amount of exaggeration in that statement but it underlines just how highly les Toulousains regard their English visitors, who have 12 wins from 14 starts in all competitions this term. There will be no complacency this time.
The hosts have good reason to be wary when you consider Saracens' record on the road this season. 22-12 victors over Harlequins at the Stoop and 29-8 winners over Gloucester at Kingsholm last week, they certainly can travel.
Toulouse are coming off a home win against Clermont, which speaks volumes of their improving form and no team takes this competition more seriously than les rouge et noir.
Toulouse have the best stats in the competition in terms of defenders beaten, 116. The most impressive stat however belongs to hulking number eight Louis Picamoles, who has bumped off 22 tacklers in Europe this season.
Saracens have scored more tries than anyone else - 17 - and have also score the most points - 142 - in the four previous rounds.
Toulouse have made three changes to the side that beat Clermont last week, all in the pack as Clement Poitrenaud keeps his place in midfield with Gael Fickou one of only two backs the bench.
Pumas lock Patricio Albacete comes into the seocnd-row ahead of French international Romain Millo-Chluski, who takes a place amongst the replacements.
In the front-row, Census Johnston returns at tighthead, Springbok hooker Chiliboy Ralepelle starts ahead of Christopher Tolofua while Schalk Ferriera is preferred to countryman Gurthrö Steenkamp at loosehead.
Meanwhile, Chris Wyles replaces Marcelo Bosch at centre in Saracens' only change to the side that beat Gloucester last weekend - the Argentine international misses out with a slight knock.
On the bench, loosehead prop Richard Barrington comes into the squad to replace Rhys Gill, whilst George Kruis , Ernst Joubert and Duncan Taylor are also included.
Toulouse: 15 Maxime Médard, 14 Yoann Huget, 13 Yann David, 12 Clement Poitrenaud , 11 Hosea Gear, 10 Jean-Marc Doussain, 9 Jano Vermaak, 8 Louis Picamoles, 7 Thierry Dusautoir (c), 6 Yannick Nyanga, 5 Patricio Albacete, 4 Yoann Maestri, 3 Census Johnston, 2 Chiliboy Ralepelle, 1 Schalk Ferriera.
Replacements: 16 Christopher Tolofua, 17 Gurthrö Steenkamp, 18 Yohan Montes, 19 Romain Millo-Chluski, 20 Joe Tekori, 21 Yacouba Camara, 22 Sebastian Bézy, 23 Gael Fickou.
Saracens: 15 Alex Goode, 14 Chris Ashton, 13 Chris Wyles, 12 Brad Barritt, 11 David Strettle, 10 Owen Farrell, 9 Neil de Kock, 8 Billy Vunipola, 7 Kelly Brown, 6 Jackson Wray, 5 Alistair Hargreaves, 4 Steve Borthwick (capt), 3 James Johnston, 2 Schalk Brits, 1 Mako Vunipola.
Replacements: 16 Jamie George, 17 Richard Barrington, 18 Matt Stevens, 19 George Kruis, 20 Ernst Joubert, 21 Richard Wigglesworth, 22 Charlie Hodgson, 23 Duncan Taylor.
Date: Sunday 12th January
Venue: Stade Ernest Wallon, Toulouse
Kick-off: 16:00 local (15:00 GMT)
Referee: Alain Rolland