Saracens moved to the top of Heineken Cup Pool 1 on Sunday thanks to a 19-13 victory over Munster in a gripping tussle at Vicarage Road.
The results leave Sarries two points ahead of Racing Metro and three clear of Munster with two rounds still to play.
Crucially, the English club must still travel to Paris, where Munster were defeated in Round One.
The scored was locked at 10-all at the break after Doug Howlett scored to cancel out David Strettle's try for the hosts.
Ronan O'Gara put Munster in front from the kicking tee early in the second period but Owen Farrell was able to land three more shots at goal to give Saracens a hard-fought victory.
The win gave Saracens their first victory over the Irishmen in five attempts, after making six changes to the side which lost at Thomond Park last week.
Rob Penney meanwhile, kept the faith with his Munster side, making only one change, Casey Laulala replacing the injured Keith Earls in the back line.
Early Saracens play took them through the phases, but Farrell missed the first chance to get the scoreboard ticking over, just wide with his drop goal attempt after only seven minutes.
The England international made amends, scoring a penalty kick two minutes later, before his opposite number O'Gara matched him after 16 minutes.
Strettle, on his return to the side, raced on to a perfectly-weighted grubber kick from Richard Wigglesworth, dotting down in the corner for the first try of the game halfway through the first period.
Munster though, kept the pressure on the home side, and Howlett was the beneficiary of an intercepted Farrell pass on halfway, and supported James Downey, who made the interception. O'Gara equalised with the conversion.
The sides entered half-time on level terms, after Farrell missed a penalty attempt from the 22. Farrell missed a second penalty attempt shortly after the restart, before O'Gara showed him the way, as he slotted a long distance kick on 51 minutes to take the lead for the Irishmen.
A downpour midway through the game led to a series of handling errors from both sides. Farrell equalised on 56 minutes, before regaining the lead with a long-distance kick on the hour.
Will Fraser was yellow carded for a high tackle, and that gave Munster the chance to move out of their own half, as much of the period up to then had been played in the Irishmen's territory.
O'Gara lined up a drop-goal attempt at the end of a 22-phase play, but his kick was just wide, as his side put the pressure on Saracens' 14 men.
Munster held Saracens inside their own half for the duration of that sin-binning, but were unable to take real advantage, O'Gara missing a long-distance chance to level the scores with less than ten minutes remaining.
Back to a full complement, Saracens regained the upper hand, and it was Fraser who made amends for his earlier indiscretion, pressurising Munster into a penalty, giving Farrell the chance to score his fourth penalty of the game with only three minutes to play.
The fly-half accepted, and with a six point lead, the home side held out for the win which saw them leapfrog Munster to lead the pool going into the final qualifying stages.
Pens: Farrell 4
Yellow card: Fraser (62nd min - high tackle)
Pens: O'Gara 2
Saracens: 15 Alex Goode, 14 Chris Ashton, 13 Joel Tomkins, 12 Brad Barritt, 11 David Strettle, 10 Owen Farrell, 9 Richard Wigglesworth, 8 Kelly Brown, 7 Will Fraser, 6 George Kruis, 5 Mouritz Botha, 4 Steve Borthwick (capt), 3 Matt Stevens, 2 Schalk Brits, 1 Rhys Gill.
Replacements: 16 John Smit, 17 Mako Vunipola, 18 Petrus du Plessis, 19 Eoin Sheriff, 20 Ernst Joubert, 21 Neil de Kock, 22 Charlie Hodgson, 23 Chris Wyles.
Munster: 15 Felix Jones, 14 Doug Howlett (capt), 13 Casey Laulala, 12 James Downey, 11 Simon Zebo, 10 Ronan O'Gara, 9 Conor Murray, 8 James Coughlan, 7 Peter O'Mahony, 6 Dave O'Callaghan, 5 Donnacha Ryan, 4 Donncha O'Callaghan, 3 BJ Botha, 2 Mike Sherry, 1 David Kilcoyne.
Replacements: 16 Damien Varley, 17 Wian du Preez, 18 Stephen Archer, 19 Billy Holland, 20 Peter Butler, 21 Duncan Williams, 22 Ian Keatley, 23 Luk O'Dea.
Venue: Vicarage Road
Referee: Pascal Gauzere (France)
Assistant referees: Jérôme Garces (France), Jean-Luc Rebollal (France)
Television match official: Gérard Borreani (France)