From the Guardian archiveBoxing

Dempsey knocks out Brennan to retain world heavyweight crown – archive, 1920

16 December 1920: The US fighter delivered a knock-out-blow in the twelfth round of a bloody contest last night at Madison Square Garden

Jack Dempsey, heavy weight boxing champion of the world, retained his title in a fight at New York on Tuesday with “Bill” Brennan. The contest was one of fifteen rounds, and Dempsey won with a knock-out-blow in the twelfth. Jess Willard, who took the title from Jack Johnson and was afterwards dispossessed of it by Dempsey, has challenged the winner.

New York, Tuesday (received yesterday)
The first round opened with Dempsey leading with his right to the head. There was then a close exchange of lefts and rights, followed by frequent clinches. Both men worked fast, but the round seemed a shade in favour of Dempsey.

The second round started with a mix-up, followed by short lefts and rights at close quarters. Brennan got in a good left to the stomach, and two hefty uppercuts, and seemed to have the best of the round.

The men rushed into a clinch on the opening of the third round, which at first was fairly even. Brennan’s mouth was bleeding freely. Dempsey got in some powerful jolts in the last minute.

The fourth round was marked by a good deal of ineffective work at close quarters and an exchange of body blows. Brennan sent a right twice to the head, the champion replying with a stiff left to the ear and two vicious rights to the head. Dempsey seemed to be putting more steam into his blows and undoubtedly had the better of this round.

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In the fifth, Dempsey opened with three hard rights to the stomach and ribs, forcing Brennan into a neutral corner, and then repeating with hard rights to the body when Brennan got back to the centre of the ring.

In the sixth round the men exchanged hard body blows with both hands, and in the subsequent mix-up Dempsey scored heavily on Brennan’s wind, winning the round with a good margin.

Rounds seven and eight had no special feature, Brennan’s returns seeming to be much lighter than the forceful drives of Dempsey.

In the ninth round there was much in-fighting, Dempsey scoring with lefts and rights, while Brennan replied with hooks to the face and head, and seemed to be improving.

In the tenth round, Dempsey almost dropped Brennan with a left across to the jaw. Brennan rocked on his feet, but pulled himself manfully together. He seemed pretty used up when the bell rang.

Dempsey had the better of the exchanges throughout the eleventh round, Brennan falling in clinches to save himself. Nevertheless he received severe joltings with short arm jabs.

The end came suddenly. The champion registering a stunning right to the heart and a left hook to the stomach. Brennan seemingly crumpled up, and as he tottered to the floor he was sent sprawling to the ropes with a right smash. He took the count rolling about the ring in a vain endeavour to regain his feet, and his seconds jumped in and carried him away. Dempsey retired from the fight undamaged, save for a split ear which bled profusely.

Jack Dempsey vs Bill Brennan, December 14, 1920, via Youtube

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