Lutsenko (Astana) finished seven seconds ahead of Frenchman Fabien Grellier (Direct Energie) and 11 seconds clear of Domenico Pozzovivo (Bahrain-Merida) on the 5.7km climb that averaged 10.5 per cent.
The defending race champion, who was second on this finish to teammate Miguel Lopez last season, distanced Pozzovivo and then caught and surpassed Grellier on the final slopes to extend his overall lead.
Lutsenko, 26, appeared less exhausted than his rivals at the finish but the effort quickly caught up after an interview in Italian, with the Kazakh national champion asking to do English rounds later at the podium ceremony where he made an emotional dedication.
“I want to dedicate this victory to my wife, who had a miscarriage of our twins last December. With these three wins, I want to honour them all. My wife and I went through a very difficult time together,” Lutsenko said.
“The team supported me all the time in this period, and I’m happy I can reward them as well for this support. It was a perfect race for us, as everything went exactly how we planned.
“The team protected me very well until the second part of the climb and then it was up to me to follow my most important rivals. My main goal was to keep the red jersey, but when I saw the last man from the breakaway just in front of me, I gave it my all and took the victory. It was an important and emotional victory for me and the team.”
Meanwhile, Grellier made an equal pitch for play of the day under the hot desert sun. Fans and media perched on higher slopes of the mountain watched in anticipation as the 24-year-old led the race on the snaking climb, swaying all over the road. Grellier spent the day in the main six-man escape and was only caught a few hundred metres from the finish line.
“I didn’t know that climb, now I do. I’ve climbed different climbs in my life, but this is maybe the hardest I’ve had. It will stick in my mind for a long time,” he said via a translator.
“My sports director was telling me, ‘Don’t look back, don’t look back’. I just gave everything I had in myself the last 2km, I was sprinting to the line. I think my muscles will hurt tonight but I have no regret.”
Asked if he believed he could have won the stage, Grellier referred to tactics and circumstance.
“My teammate, Romain Cardis, was pulling for me [in the breakaway] and that’s because I thought I could win. I wouldn’t have asked him to pull if I didn’t think I had a shot at this,” he said.
“It’s so steep it takes minutes and minutes just to cover 500m, so it’s hard to consider and think whether you’re going to make it or not. I just tried.”
The Tour of Oman finishes today with stage six – a flat run for pure sprinters around Muscat. Lutsenko’s victory doubled as Astana’s ninth of the season. He leads the race with a 44 second buffer on Pozzovivo and 47 second advantage on Jesus Herrada (Cofidis).