Kauto Star returned to action with a hard-fought victory in the JNwine.com Champion Chase at Down Royal.
But the dual Cheltenham Gold Cup winner was made to pull out all the stops against two young horses certain to win more races in Sizing Europe and China Rock.
Ruby Walsh nursed Paul Nicholls' 10-year-old round and four fences from home all three horses were still going well enough. However, Kauto Star's class eventually shone through and the 4-7 favourite added yet another Grade One to his incredible haul, with Sizing Europe seeing out the three-mile trip well for second.
The former Howard Johnson-trained Killyglen helped forced the early pace with China Rock never far behind. Mossbank, off the track for 927 days, loomed up large half a mile out but not surprisingly his absence eventually took its toll.
With the race hotting up, last season's Arkle winner Sizing Europe looked a huge threat to Kauto Star but try as Andrew Lynch might, he could never quite get on terms with the four-times King George winner.
Kauto Star looked to be idling a little after the last but he was kept up to his work to beat Sizing Europe by four lengths with a neck back to China Rock.
As Kauto Star was last seen in public taking a heavy fall in the Gold Cup, Nicholls was especially pleased with his jumping
The trainer said: "It was just the start we wanted, he jumped great today which is just what we wanted him to do and we can go on from here. They all thought it rode a good race and the ground was quite testing so we are chuffed to bits.
"You never know after having a fall like he had whether they will lose their confidence, but we did a lot of work in the spring and Ruby rode him earlier in the week, his confidence is back. Stamina won the day.
"I shall know fairly quickly during the week whether he'll go for the Hennessy as I'll be able to tell how hard a race he had and what effect the journey has had. If he's back fresh and well and cantering he might go to the Hennessy, but if I find he's a bit quiet and I need to give him a couple of weeks off he won't go for it."