In front of a spectacular, snow topped mountain range in Alaska, the giant animals took each other to task, with one even taking a crafty low side-swipe.
Despite one of the bears holding a definite weight advantage, the pair grappled and exchanged blows.
But after 15 minutes of hard combat they seemed happy to call it a draw and went hunting for salmon in a nearby river.
The incredible duel was captured on camera by amateur photographer Scott Cromwell during a special bear spotting trip.
He flew for six hours from Homer, Alaska, to Hallow Bay, which is part of the Katmai National Park, also in Alaska, just to see the majestic animals.
Scott, 38, said: 'The guide and pilot flew us over a known area and we spotted a few bears so we landed on the beach a few hundred yards away from them.
'We walked up to about 250ft from them and stood and watched from a dry part of the river bed.
'They instantly quit fishing for salmon in the river and ran out in the open in between us and the mountains.
'The smaller bear came out into the open first but then the bigger one galloped after it making a lot of noise.
'They circled around the whole large area a couple of times and then started wrestling right in front of us - we were no more than 100ft away.
'I couldn't believe what was happening - we had only just got off the plane and this all seemed to have happened instantly.'
Television repairman Scott said the bears battled for 15 minutes before getting bored or hungry and returning to hunting for salmon.
He added: 'I was leaning over the whole time while shooting, trying to get as close to the ground as possible without including any grass in the foreground.
'It truly was the most enjoyable 15 minutes of my life. In fact the whole trip was the best six hours of my life.
'Seeing bears this close really is incredible.'