Willie Mullins recorded his third victory on day one of the Cheltenham Festival and his 57th winner at the meeting following 9/2 chance Rathvinden's narrow success in the G2 National Hunt Chase over four miles.
Travelling sweetly entering the home straight under Mullins' son Patrick, the 10-year-old son of Heron Island denied Anthony Honeyball's Ms Parfois (11/2) in the closing stages to score by half a length.
Front-runner Sizing Tennessee (8/1) was 21 lengths further back in third.
Patrick Mullins wins on Rathvinden
Successful with Footpad in the G1 Racing Post Arkle Novices' Chase and Benie Des Dieux in the G1 OLBG Mares' Hurdle, the Closutton handler, registering a 54.46/1 treble said: "We're delighted. The horses are performing well.
"The first two days were tough last year, but thankfully things are better this time around and it's been a fantastic day for us."
Rathvinden did not return to the winners' enclosure after the race but the trainer reported the gelding to be fine.
He continued: "Rathvinden was slightly wobbly. He is fine but like any athlete, he got tired and just was wobbling slightly, so that's why he didn't come back into the winner's enclosure.
"Knowing the way Patrick rides given his body language, I knew he had a bit in the tank.
"I thought he would win it a bit easier than he did but Ms Parfois was very tough in second despite not jumping the second-last great, so that was an excellent performance from that mare.
"They pulled a long way clear and it was a tough finish after four miles on that ground so full marks to both riders and horses as it was nip and tuck the whole way.
"I think one day, he could be a Grand National horse as he jumps, stays and travels."
Rathvinden was providing Mullins with a second victory in the contest following Up For Review's success in the 2013 edition.
Patrick Mullins said: "He's 100%. I got down off him [at the finish] to undo his over-girth, and the vets here are being very cautious and wouldn't let me get back on him, but he's 100%. He's given me everything, yes, but I'm pretty tired myself, too! He jumped great and settled fantastically. He's the ideal candidate for this race because he's got lots of experience and a bit of age [the horse is 10].
"I'm getting on now because it is 10 years since Cousin Vinny [his first Festival victory, winner of the 2008 Weatherbys Champion Bumper]. There are a lot of people who are more talented me and work harder than me who don't get the opportunities I get, so I have to make the most of them."
Asked to describe how the race panned out, he said: "I wanted just to drop out and settle and get him relaxed, which he did. They went a good gallop and he jumped well. I was just taking my time, and then wanted to make my bid after the last, having watched the other races, and the plan worked out for once.
"It's drying up out there and [the ground] is getting tacky now - it would be better for a shower of rain. But my horse is very tough."
4.50pm National Hunt Chase (Grade 2)
1 RATHVINDEN (Ronnie Bartlett) Willie Mullins IRE 10-11-06 Mr Patrick Mullins 9/2
2 MS PARFOIS (M Chapman) Anthony Honeyball 7-10-13 Mr Will Biddick 11/2
3 SIZING TENNESSEE (Ann & Alan Potts Ltd) Colin Tizzard 10-11-06 Mr Barry O'Neill 8/1
4/1 fav Jury Duty (PU)
Distances: ½, 21
Tote Win: £5.30
Places: £2.20, £1.90, £2.70
Willie Mullins - 57th winner at The Festival
Mr Patrick Mullins - 4th winner at The Festival
BetBright Cup - standings after six races
Great Britain 3