Josh Warrington edged a tough contest with British rival Kid Galahad to retain his IBF world featherweight title with a split-decision points win.
Warrington, 28, hoped the contest would be his last in his home city of Leeds as he eyes potential unification fights in the United States.
Galahad, 29, frustrated him early on and switched his stance to confuse.
He frequently grappled to kill any flow in the fight but the champion earned a split 116-112, 116-113 113-115 verdict.
"I think I did enough to nick it in the last two rounds because it was nip and tuck but you cannot win a title by hitting pot shots," said Warrington.
"They are not going to all be pretty and I'm glad I got through it, so hopefully there is a unification fight next."
Warrington admitted afterwards he felt "tense" given the bout was a gateway to potential unification bouts and there was a genuine rivalry on show, with the champion frequently raising his Sheffield opponent's two-year backdated drugs ban from 2016 in the build-up.
Such was the animosity, British middleweight champion Liam Williams - who trains in the same gym as Galahad - stood ready with an umbrella to shield the challenger from the possibility of any objects being thrown during the ring walk.
But when the action started, Galahad lined up in the southpaw stance and seemed poised, slipping shots and throwing a left hand through the guard in the second round.
Warrington landed a right hand followed by a left in a smart flurry in the third but Galahad was resorting to single shots before tying his opponent up. In doing so he ensured the relentless work-rate Warrington had built his career on could never truly break out as the fight became scrappy and stop-start.
He was warned for excessive holding around the midway point but by that stage he had silenced much of the home crowd, who expected Warrington - a 1-3 favourite with bookmakers - to make light work of a man he had beaten twice at amateur level.
A cuffing right hand from Warrington caught the eye in the seventh but the scoring will undoubtedly prompt controversy, as there were clear pockets of action where Galahad's movement was smart and his infrequent punching accurate.
Warrington's father and trainer Sean O'Hagan told his fighter Galahad was "having the night of his life" and implored the champion to "do it for nine minutes" in the closing three rounds if he was to keep his belt.
And in truth, the final few rounds were where Warrington showed glimpses of the work-rate which earned him eye-catching wins over Lee Selby and Carl Frampton in 2018.
He still soaked up single shots - a smart uppercut in the 10th and a straight left in the 12th in particular - but drove forward to land work of his own and take a win that can perhaps take him and his army of fans across the Atlantic Ocean at last.
'Robbery' or 'right result'?
Warrington's father and trainer Sean O'Hagan: "That was a very tight fight and it came down to the last two rounds. I think it was terrible refereeing and how many warnings do you need before deducting points? That was not one of Josh's best performance and we were at about 70% there tonight. We will have to be better than than Stateside."
BBC Radio 5 Live analyst Jamie Moore: "I believe he has done enough. It was a really close contest but I scored it nine rounds to three to Josh Warrington."
BBC Radio 5 Live analyst Andy Lee: "Those rounds were extremely close and I'm sure there are people in the Kid Galahad corner who will feel it was unjust but I think it was just the right result."
Boxing promoter Eddie Hearn: "Head up Kid Galahad. Clear winner tonight."
Super-middleweight Billy Joe Saunders: "Robbery. Kid Galahad put it all on the line."
Former world super-middleweight champion Caleb Truax: "Dull fight but Galahad did a brilliant job of negating Warrington's activity. Didn't score it round for round but I think Galahad won it."
Where next for Warrington?
Warrington had talked of big American fights long before Galahad was made his mandatory challenger and the three other belt holders at 126lbs - WBA champion Leo Santa Cruz, WBC belt-holder Gary Russell Jr and WBO king Oscar Valdez - are all viable options.
"I felt like I was one more hurdle away from getting to the States and had I slipped now, it would have been even further away so I think I put pressure on myself at how bad I wanted it," said Warrington.
"There's no-one left for me to fight over here. I don't want to be coming back here and defending the title against some bloke who works at the car-wash on the York Road.
"If I can get my own way, I'd like to go to America for the memories and the experience."
BBC Radio 5 Live analyst Lee added: "He knew he had to just get past this one and those kind of fights are hard to get yourself up for.
"How many times can he go to the well? He has had three gruelling fights and he needs to go to the US now. If he has to fight in the UK again he will not have the same performances he has had before."
Mexico's Valdez - who has 26 wins from 26 and 20 via stoppage - has been talked up as the most likely opponent waiting for Warrington.
Such a bout in Las Vegas or New York will allow the Leeds fighter the chance to take his huge following to America in what many have said could offer a throwback to some of the rowdy nights former two-weight world champion Ricky Hatton once enjoyed Stateside.
His performance will have to improve but the wins over Selby and Frampton made clear the fact Warrington can rise for key occasions.