The 46-13 victory capped a good week for Gatland, who has also secured the services of captain Lawrence Dallaglio on a new two-year contract.
Gatland said: "We are absolutely delighted he has re-signed. We struck a deal during the week".
Yesterday's win put the Zurich Premiership champions top of Pool Six ahead of their final group game against Perpignan for a place in the quarter-finals.
Wasps had a John Rudd hat-trick of tries to thank for setting up the emphatic victory yesterday, with Ayoola Arinle, Johnny O'Connor and Tim Payne also crossing to add to a penalty try.
Former Ireland coach Gatland was impressed with the way a young Wasps side comfortably brushed aside the Italians.
"We had a lot of youngsters out there and to score seven tries and 40 odd points we're happy with that," he said. "Perpignan only beat them by 17-11 last week."
The win gives the Londoners 19 points, four more than Perpignan and the Celtic Warriors and Gatland is desperate to beat the French side and earn a home tie in the last eight stage.
"We desperately want a home quarter-final so I think to do that we need to get a result next week we need to win the match," he added.
"Obviously everyone raises their game when they are playing Wasps and the personnel we have playing so they'll be tough to be beat down there."
One cloud on his horizon was the injury to Stuart Abbott that is expected to keep the England centre out of the early matches of the RBS 6 Nations Championships that begins on 15 February.
"We think he'll be out for around two to three weeks. It's just a recurrence of the ankle that hasn't been right since the Barbarians match. We don't know fully the assessment but he didn't look too good coming off the field," he said.
Wasps scorers: Tries - Penalty, Rudd 3, Erinle, O'Connor, Payne. Cons: A. King 4. Pens: A. King.
WASPS: van Gisbergen, Voyce, Abbott, Denney, Rudd, A. King, Richards, Payne, Leota, Green, Purdy, Skivington, Volley, O'Connor, Worsley. Replacements: Roiser for van Gisbergen (78), Erinle for Abbott (15), Biljon for Richards (71), Mackenzie for Payne (69), Gotting for Leota (64), Lock for Volley (69), Clarke for Worsley (79).
Ghial Amatori & Calv scorers: Tries: Mulieri. Cons: Fraser. Pens: Fraser 2.
GHIAL AMATORI & CALV: Vaccari, Mulieri, Vodo, Zanoletti, Mazzuccato, Fraser, Canavosio, Davo, Moretti, Castrogiovanni, Mastrodomenico, Ngauamo, Mayerhofler, Zaffiri, De Rossi. Replacements: De Carli for Vaccari (40), Raineri for Vodo (78), Griffen for Canavosio (64), Ravazzolo for Davo (40), Purll for Castrogiovanni (53), Mandelli for Mastrodomenico (53).
Referee: Rob Dixon (RFU).
Leeds 22 Toulouse 31
By Scott Dougal
TOULOUSE set their sights on Edinburgh and the top spot in pool two with a hard-fought Heineken Cup win over Leeds at Headingley.
The European champions beaten by Edinburgh at the start of the campaign - can overhaul the Gunners when the two sides meet in France next weekend.
But they were tested by a Leeds side who had looked down and out at 24-3 down early in the second half.
It was a much improved performance by Leeds in contrast to their meek surrender to Edinburgh here last Sunday.
Leeds coach Phil Davies made seven changes to the side that lost 23-0 to the Gunners.
England international Dan Scarbrough and Liam Botham returned to the wings.
Phil Christophers moved from wing to centre while Scotland international Gordon Ross was reinstated at fly-half.
In the pack, Gary Howell replaced Matt Holt at prop, Stuart Hooper returned to the second row after a three-week absence through injury. Aaron Persico and Colm Rigney were also welcomed back.
Leeds scorers: Tries: Scarbrough, Albanese, Regan. Cons: Ross 2. Pens: Ross.
LEEDS: Cardey, Botham, Christophers, Snyman, Scarbrough, Ross, Walker, Shelley, Regan, Powell, Hooper, Palmer, Rigney, Persico, Popham.
Replacements: Albanese for Botham (48), Rawlinson for Regan (77), Kerr for Powell (48), Hyde for Rigney (48), Murphy for Popham (67).
Toulouse scorers: Tries: Jean-Jean, Brennan, Desbrosse, Labit. Cons: Elissalde 4. Pens: Elissalde.
TOULOUSE: Poitrenaud, Ntamack, Desbrosse, Baby, Clerc, Michalak, Elissalde, Collazo, Bru, Poux, Gerard, Brennan, Bouihlou, F. Maka, Labit.
Replacements: Heymans for Poitrenaud (74), Jean-Jean for Baby (43), Delaigue for Elissalde (75), Servat for Bru (54), Millochlusky for Gerard (72), I. Maka for F. Maka (60).
Ref: Greg Davies (SRU).