The 2001 and 2002 Heineken Cup winners had to dig deep before a try by flanker Neil Back edged it for the Tigers with extra time fast running out while London Wasps will be the England No 1 seeds after beating Gloucester 39-3 in the Zurich Premiership final at Twickenham later the same day.
However, the Heineken Cup pecking order of the French will only be settled at the end of their domestic season, when recently crowned Heineken Cup champions Toulouse and Stade Francais clash in the French Championship final at Stade de France on Saturday (7 June).
Elsewhere it is all cut and dried with Leinster Lions the Irish No1 seeds; the new Llanelli region and Edinburgh Rugby the standard bearers for Wales and Scotland respectively and Benetton Treviso winning the Italian Championship title last Saturday (31 May) to carry the main Azzurri hopes.
In the French semi-finals last weekend Toulouse beat Agen 22-16 and 2001 Heineken Cup finalists Stade Francais triumphed 32-9 over Biarritz Olympique to set up a mouth-watering final in Paris.
And in Padova, Benetton Treviso made sure of the Italian domestic title as they beat Ghial Calvisano 34-12 to return to the premier European club rugby tournament they missed out on last season.
"It is great to be back in the Heineken Cup," said Treviso coach Craig Green, the former All Black wing. "Our win on Saturday means we are back at the top of Italian rugby and by playing in the Heineken Cup we will be competing against the very best sides in Europe.
"We have got a proud history in the tournament and we are looking forward to next season and being part of the Heineken Cup once again."
WHO'S WHO IN THE 2003/2004 HEINEKEN CUP
ENGLAND: 1) London Wasps, 2) Gloucester, 3) Northampton Saints, 4) Sale Sharks, 5) Leeds Tykes, 6) Leicester Tigers
FRANCE: (rankings to be determined after French Championship final at Stade de France on 7 June, 2003): Agen, Biarritz Olympique, Bourgoin, Perpignan, Stade Francais, Toulouse
IRELAND: 1) Leinster Lions, 2) Munster, 3) Ulster
ITALY: 1) Rugby Treviso, 2) Ghial Calvisano
SCOTLAND: 1) Edinburgh Rugby, 2) Borders
WALES: 1) Llanelli Region, 2) Neath / Swansea Region, 3) Bridgend / Pontypridd Region, 4) Ebbw Vale / Newport Region, 5) Cardiff Region
LEADING SCORERS 2002 / 2003
107 Stephen Jones (Llanelli)
103 Ronan O'Gara (Munster)
101 Ludovic Mercier (Gloucester)
97 Manny Edmonds (Perpignan)
84 Brian O'Meara (Leinster Lions)
83 Barry Everitt (London Irish)
74 Jean-Baptiste Elissalde (Toulouse)
73 Felipe Contepomi (Bristol Shoguns)
72 Dimitri Yachvili (Biarritz Olympique)
70 Alexandre Peclier (Bourgoin)
7 Garan Evans (Llanelli), Vincent Clerc (Toulouse)
6 Gordon D'Arcy (Leinster Lions)
5 Yannick Delaigue (Toulouse), Denis Hickie (Leinster Lions), Marcel Garvey (Gloucester), Martyn Madden (Llanelli)
25 Ludovic Mercier (Gloucester)
21 Jean-Baptiste Elissalde (Toulouse), Ronan O'Gara (Munster)
23 Stephen Jones (LLanelli)
22 Brian O'Meara (Leinster Lions)
19 Barry Everitt (London Irish)
3 Manny Edmonds (Perpignan), Barry Everitt (London Irish), Alexandre Peclier (Bourgoin), David Humphreys (Ulster