Enisei-STM registered a shock win over Brive while Harlequins, Dragons, London Irish and Sale Sharks claimed victories over Calvisano, Pau and Edinburgh and Castres respectively.
Enisei-STM 10-7 Brive
Enisei-STM registered the biggest shock of this year's Challenge Cup when they beat Brive 10-7 in Sochi on Saturday.
The opening 30 minutes was a tense affair but Enisei-STM hooker Nazir Gasanov gave his side an unlikely lead when he crashed over for the opening try.
The Siberian-based side extended their lead shortly before the break when Iurii Kushnarev slotted a penalty which meant the tournament debutants led 10-0 at half-time.
Brive struck back after the break with a try from Thomas Acquier and they uppped the ante in their quest for the victory in the second stanza, but Enisei-STM's defence held firm.
The result means Enisei-STM are now just two points behind third-placed Brive in Pool 1.
Enisei-STM: 15 Igor Kurashov, 14 Robert Malneek, 13 David Kacharava, 12 Mikhail Babaev, 11 Denis Simplikevich, 10 Iurii Kushnarev, 9 Jurijs Baranovs, 8 Anton Rudoi, 7 Mikhail Sidorov, 6 Plavel Butenko, 5 Viacheslav Krasylnyk, 4 Uldis Saulite, 3 Innokentiy Zykov, 2 Nazir Gasanov, 1 Alexey Volkov.
Replacements: 16 Stanislav Selskii, 17 Andrei Polivalov, 18 Evgenii Pronenko, 19 Andrey Temnov, 20 Ramil Gaisin, 21 Alexey Shcherban, 22 Yaroslav Rechnev, 23 Dmitrii Krotov.
Brive: 15 Anderson Neisen, 14 Atila Septar, 13 Arnaud Mignardi, 12 Thomas Laranjeira, 11 Benito Masilevu, 10 Romain Sola, 9 Nicolas Bézy, 8 William Whetton, 7 Poutasi Luafutu, 6 Hugues Briatte, 5 Wilhelm Steenkamp, 4 Victor Lebas, 3 Yusuf Tuncer, 2 Francois Da Ros, 1 Damien Lavergne.
Replacements: 16 Thomas Acquier, 17 Goderzi Shvelidze, 18 Kevin Buys, 19 Fabien Sanconnie, 20 Said Hireche, 21 Péniami Narisia, 22 David Delarue, 23 Jean-Baptiste Pejoine.
Referee: Vlad Iordachescu (Romania)
Calvisano 10-50 Harlequins
Harlequins consolidated their position at the top of Pool 3 with a convincing 50-10 victory at Calvisano on Saturday.
As the scoreline suggests, Quins were in a rampant mood and they outscored their hosts eight tries to one with Luke Wallace leading the way with a brace.
Wallace crossed for the opening score as early as the first minute and the visitors extended their lead when Mark Lambert scored their second try five minutes later.
Quins continued to dominate as the half progressed and there were further tries from Jack Clifford, Wallace and Ross Chisholm.
Calvisano's only points came in the 15th minute via a Filippo Buscema penalty which meant Quins held a comfortable 29-3 lead at the interval.
The second-half was highlighted by several errors from both sides with the first points of the half only registered in the 55th minute when Matt Hopper crossed for Quins' fifth try.
Five minutes later, Maxime Mbanda crossed for the home side's only try before late five-pointers from Kyle Sinckler and Charlie Walker sealed the visitors' victory.
Tries: Wallace 2, Lambert, Clifford, Chisholm, Hopper, Sinckler, Walker
Cons: Botica 5
Calvisano: 15 Matteo Minozzi, 14 Ben De Jager, 13 Pablo Canavosio, 12 Alberto Chiesa, 11 Marco Susio, 10 Filippo Buscema, 9 Riccardo Raffaele, 8 Renato Giammarioli, 7 Maxime Mbanda, 6 Nicola Belardo, 5 Davide Zanetti, 4 Agustin Cavalieri, 3 Rudy Biancotti, 2 Lorenzo Giovanchelli, 1 Sami Panico.
Replacements: 16 Luhandre Luus, 17 Gabriele Morelli, 18 Salvatore Costanzo, 19 Michele Andreotti, 20 Jim Tuivaiti, 21 Matteo Archetti, 22 Daniele Di Giulio, 23 Giacomo De Santis.
Harlequins: 15 Tim Swiel, 14 Ross Chisholm, 13 Matt Hopper, 12 Winston Stanley, 11 Tim Visser, 10 Ben Botica, 9 Karl Dickson, 8 Jack Clifford, 7 Luke Wallace, 6 Archie White, 5 Charlie Matthews, 4 James Horwill, 3 Will Collier, 2 Rob Buchanan, 1 Mark Lambert.
Replacements: 16 Dave Ward, 17 Owen Evans, 18 Kyle Sinckler, 19 George Merrick, 20 Kieran Treadwell, 21 Tito Tebaldi, 22 Harry Sloan, 23 Charlie Walker.
Referee: Ben Whitehouse (Wales)
Dragons 22-0 Pau
Dragons moved clear at the top of Pool Two after registering an easy victory over Pau at Rodney Parade.
Dorian Jones was the home side's hero, contributing 17 points to the win via a try and four penalties. Jones opened the scoring with two penalties before Sarel Pretorius scored the game's first try after an 80-metre run.
Jones slotted two more three-pointers from the kicking tee before crashing over for his side's second try midway through the second-half.
Tries: Pretorius, Jones
Pens: Jones 4
Dragons: 15 Carl Meyer, 14 Tom Prydie, 13 Adam Hughes, 12 Adam Warren, 11 Ashton Hewitt, 10 Dorian Jones, 9 Sarel Pretorius, 8 Taulupe Faletau, 7 Ollie Griffiths, 6 Lewis Evans, 5 Rynard Landman, 4 Matthew Screech, 3 Brok Harris, 2 T Rhys Thomas, 1 Phil Price.
Replacements: 16 Elliot Dee, 17 Lloyd Fairbrother, 18 Shaun Knight, 19 Cory Hill, 20 Ed Jackson, 21 Luc Jones, 22 Jason Tovey, 23 Ross Wardle.
Pau: 15 Romain Buros, 14 Marika Vunibaka, 13 Jale Vatubua, 12 Watisoni Votu, 11 Elijah Niko, 10 Charly Malie, 9 Samuel Marques, 8 Brice Monzeglio, 7 Josefa Ulago Domolailai, 6 Sean Dougall, 5 Claude Dry, 4 Cameron Pierce, 3 Euan Murray, 2 Mehdi Boundjema, 1 Chris King.
Replacements: 16 Thomas Bianchin, 17 Julien Jacquot, 18 Giorgi Natsarashvili, 19 Daniel Ramsay, 20 Loic Bernad, 21 Thierry Lacrampe, 22 Pierre Dupouy, 23 Mosese Ratuvou.
Referee: Craig Maxwell-Keys (England)
London Irish 38-6 Edinburgh
London Irish secured an emphatic 38-6 victory over Edinburgh in their Pool Five clash at the Majedski Stadium.
The Exiles outscored their hapless visitors six tries to none with Andy Fenby leading the way with an impressive hat-trick.
Edinburgh were fastest out of the starting blocks and held a 0-6 lead inside the first 10 minutes after Greig Tonks landed two penalties.
That would be the last time the visitors would score points as Fenby crossed for two tries in quick succession before Alex Lewington also dotted down.
With Johnny Williams scoring their bonus-point try just before the break, London Irish led 26-6 going into the dressing rooms.
Aseli Tikoirotuma went over for his side's fifth try on the hour mark before Fenby sealed the win with his third try shortly before full-time.
For London Irish:
Tries: Fenby 3, Williams, Tikoirotuma, Lewington
Cons: Geraghty 3, Brophy-Clews
Pens: Tonks 2
London Irish: 15 Sean Maitland, 14 Alex Lewington, 13 Aseli Tikoirotuma, 12 Johnny Wililams, 11 Andrew Fenby, 10 Shane Geraghty, 9 Brendan McKibbin, 8 Ofisa Treviranus, 7 Conor Gilsenan, 6 Luke Narraway, 5 Jebb Sinclair, 4 Eoin Sheriff, 3 Ben Franks, 2 Gerard Ellis, 1 Tom Court.
Replacements: 16 Jimmy Stevens, 17 Tom Smallbone, 18 Leo Halavatau, 19 David Sisi, 20 Blair Cowan, 21 Darren Allinson, 22 Theo Brophy Clews, 23 Dom Waldouck.
Edinburgh: 15 Dougie Fife, 14 Tom Brown, 13 Michael Allen, 12 Andries Strauss, 11 Otulea Katoa, 10 Greig Tonks, 9 Nathan Fowles, 8 Cornell Du Preez, 7 Hamish Watson, 6 Jamie Ritchie, 5 Alex Toolis, 4 Anton Bresler, 3 John Andress, 2 Neil Cochrane, 1 Rory Sutherland.
Replacements: 16 George Turner, 17 Grant Shiells, 18 Simon Berghan, 19 Magnus Bradbury, 20 Chris Dean, 21 Sam Hidalgo-Clyne, 22 Blair Kinghorn, 23 Damien Hoyland.
Referee: Leighton Hodges (Wales)
Castres Olympique 10-17 Sale Sharks
Sale moved up to second place in Pool 2 after picking up an impressive win at Castres on Saturday.
A try inside a minute from wing Nev Edwards set them on their way, with fly-half Joe Ford's conversion making it 7-0 at Stade Pierre Antoine.
But Castres hit back seven minutes later through outside centre Florian Vialelle and with fly-half Julien Dumora adding a penalty goal to his conversion of that try, the hosts had put themselves 7-10 in front at the change of ends.
Ford levelled matters on the hour mark with a penalty and then, with Sale plugging away to secure a huge win on the road, they did exactly that with seven minutes remaining as a penalty try was awarded, Ford adding the gloss.
Tries: Edwards, Penalty
Con: Ford 2
Castres: 15 Julien Caminati, 14 Romain Martial, 13 Florian Vialelle, 12 Romain Cabannes, 11 Louis Decrop, 10 Julien Dumora, 9 Antoine Dupont, 8 Johnnie Beattie, 7 Ibrahim Diarra, 6 Yannick Caballero, 5 Victor Moreaux, 4 Christophe Samson, 3 Yohan Montes, 2 Marc-Antoine Rallier, 1 Saimone Taumoepeau.
Replacements: 16 Julien Beziat, 17 Antoine Tichit, 18 Lucas Martinez, 19 Benjamin Desroche, 20 Mathieu Babillot, 21 Francois Fontaine, 22 Julien Seron, 23 Thomas Combezou.
Sale Sharks: 15 Tom Arscott, 14 Neville Edwards, 13 Will Addison, 12 Mark Jennings, 11 Charlie Ingall, 10 Joe Ford, 9 James Mitchell, 8 Mark Easter, 7 David Seymour, 6 Magnus Lund, 5 Andrei Ostrikov, 4 Jon Mills, 3 Brian Mujati, 2 Neil Briggs, 1 Eifion Lewis-Roberts.
Replacements: 16 Tommy Taylor, 17 James Flynn, 18 Ciaran Parker, 19 Josh Beaumont, 20 Cameron Neild, 21 Tim Jeffers, 22 Sam James, 23 Michael Haley.
Referee: David Wilkinson (Ireland)