La Bourdonnais (France) was considered the world's leading player starting about 1821 and by 1825 he had defeated the best players in England. In 1834 he returned to England in response to a challenge from McDonnell from Ireland. They played six matches between June and October in 1834 that many recognize as being for the unofficial World Championship as at the time such a title did not exist.
It was the first match of importance in the history of chess; the games were slug fests containing many opening innovations and the games were thoroughly examined and widely published.
La Bourdonnais won the first, third, fourth and fifth matches; McDonnell won the second match, and the sixth was abandoned with him leading. The overall score for La Bourdonnais was +45 -27 =13.
It was not a friendly match. La Bourdonnais didn't speak English and McDonnell didn't speak French and it is said that the only word they exchanged during the entire match was "check” as it was customary to announce in those days.
After each game, McDonnell would return to his room exhausted, where he would spend hours pacing back and forth in a state of nervous agitation. La Bourdonnais would be downstairs continuing to play until long after midnight, smoking cigars, drinking punch and gambling. The cautious La Bourdonnais was famous for the speed at which he played, often replying within seconds. The reckless McDonnell sometimes took two hours to make a move. Their personalities were also very different. La Bourdonnais was ebullient and garrulous individual, talkative and affable when he was winning and swearing like a drunken sailor when he was losing. McDonnell was taciturn and imperturbable, displaying little emotion.
As for the games, Harry Golombek thought they were generally of low quality. There were some instances of brilliance, but technique, especially in the endgame, was low. In one game McDonnell had an endgame with a R and 2Ps versus a R but did not know how to win. He lost his rook due to a blunder and lost the game. La Bourdonnais was weak in the opening. McDonnell's inaccurate defense, which often caused him to lose rather than draw, accounted for the overall lack of a draws.
These days the King's Gambit has a dodgy reputation and most of today's players wouldn't waste their time studying it. Boris Spassky was its most outstanding practitioner and he never lost a game with it. Of course he essayed it only rarely. In the 1963/64 US Championship Bobby Fischer made up his mind to play it and Larry Evans was the victim. In that game Evans chose the same ancient defense that La Bourdonnais did here.
It's easy to say that McDonnell's rash sacrifice 7.Bxf7+ was a beginner's mistake. After all, Stockfish immediately assigned it a negative 2.5 Pawn evaluation, white did not have any pieces developed with which to conduct his attack and in the process of establishing a semblance of material equality, he left his own King wide open. But, it wasn't that simple because three moves later engine analysis reveals that La Bourdonnais had but a single move, which he found, that kept the advantage. How many times have you seen the same thing in the games of guys like Nezhnetdinov or Tahl and nobody claimed their sacrifices were beginner mistakes!