Monksland narrowly got the better of Marinero in a thrilling climax to the Ryans Cleaning Chase at Galway.
High-class hurdler Monksland made a winning start to his career over fences at Gowran Park last November before placing in three consecutive Grade One events, but had not been seen in competitive action for Noel Meade since chasing home Outlander in the Flogas Novice Chase at Leopardstown in February.
The Henry de Bromhead-trained Marinero, on the other hand, opened his chasing account at Downpatrick less than three weeks ago and was the even-money favourite under David Mullins, with Monksland a 6-5 shot in the hands of Sean Flanagan.
Marinero jumped accurately at the head of affairs throughout the two-mile-six-furlong contest, with Monksland slightly less fluent.
However, he closed the gap before jumping the final fence and eventually wore down his main rival on the long run-in, getting up by a head.
Meade said: "He nearly put me out of commission before the start as he gave me a kick in the stomach, but luckily enough there is plenty of padding there!
"I'm thrilled with him and I'm thrilled with the ride he got as well. Sean knew he wasn't that wound up and that he had to hold on to him for as long as he could and he did.
"He made a few errors and if he could rule them out it would be great. He just lacks a bit of scope and he is not easy to train.
"He swims a lot and spends a lot of time in the spa, but when he is right he is not a bad horse."
Monksland is now set for a trip to Down Royal on 5 November, where both the Powers Irish Whiskey Chase and the JNwine.com Champion Chase will come under consideration.
"He really was just three-quarters ready. The race was there and I thought we won't get as good a chance to run him again before the north (Down Royal)," the trainer added.
"He might go for the three-mile race (JNwine.com Champion Chase) because I think the three miles will suit him better."
The Tu Va handler and his newly-appointed number one rider had earlier combined to land the Mervue Maiden Hurdle with the impressive Le Martalin.
The runaway Listowel bumper winner was the 4-5 favourite to make a successful start over timber and did so in some style, coming home with 17 lengths in hand.
Meade said: "He is a nice horse and has great scope. I see him being a great chaser in time.
"I presume we will go for a novice with him now somewhere."
Cheltenham Festival hero Diamond King made a seamless transition to jumping fences in the galwayraces.com Beginners Chase.
Winner of the Coral Cup before finishing fourth in the Champion Stayers Hurdle at Punchestown, Gordon Elliott's charge jumped well on his way to a 14-length triumph under Davy Russell.
Elliott said of the 4-5 favourite: "I thought he was very good and he jumped class. He will come on a lot for the run as he is not fit.
"I'd imagine he might have one more racecourse school before going straight for the Drinmore (Fairyhouse).
"I don't think he is real heavy-ground horse so he might just miss that middle part of the season, and come back in the spring for the Festivals."
Joshua Lane finally delivered on previous promise with victory in the Galway City & Salthill Publicans Rated Novice Hurdle.
Edward Harty's seven-year-old looked a top-class prospect after finishing third in the 2014 Champion Bumper at Cheltenham, but has been underwhelming since then, having failed to find the target in his first eight starts over obstacles.
JP McManus also fielded 7-4 favourite Aspen Colorado, but he was unable to reel in the owner's apparent second string, who clung on by a length and three-quarters at odds of 25-1.
Harty said: "He seems to run well fresh and he was in good form.
"We were a long time waiting, but hopefully it won't be as long for his next one."
McManus doubled up with Joseph O'Brien's 11-4 favourite All The Answers in the Galway City & Salthill Publicans Charity Handicap Hurdle.
The victory provided Barry Geraghty with his first winner in Ireland since returning from injury.
Geraghty said: "My arm is in good enough condition, I was off for 12 weeks and it takes race riding to really get you fit."