besiegen
to defeat
To be stronger and win in a fight, competition, or game.
Es gelang der Heimmannschaft, den Tabellenführer klar mit 3:0 zu besiegen.
The home team managed to clearly defeat the league leader 3-0.

to defeat
Loading your saved state.
to defeat
To be stronger and win in a fight, competition, or game.
Es gelang der Heimmannschaft, den Tabellenführer klar mit 3:0 zu besiegen.
The home team managed to clearly defeat the league leader 3-0.

“Besiegen” is an inseparable verb with the prefix “be-.” This prefix makes the verb transitive, so it always needs an accusative object (whom or what you defeat). The base verb “siegen” (to win/be victorious) is intransitive and is used without an object.
Die Mannschaft besiegte den Gegner im Finale.
The team defeated the opponent in the final.
How can you recognize the meaning? If the object is a person, a team, or an opponent, it is about a competition. If the object is a feeling, an illness, or a problem, “besiegen” means “to overcome.”
Die Heldin besiegt den Drachen in der Geschichte.
The heroine defeats the dragon in the story.
In a sports or combat context, “besiegen” is often used with the following nouns: “einen Gegner besiegen” (to defeat an opponent), “eine Mannschaft besiegen” (to defeat a team), or “einen Feind besiegen” (to defeat an enemy).
Unsere Schule hat die andere Schule im Fußballturnier besiegt.
Our school defeated the other school in the soccer tournament.
When it is about overcoming difficulties, typical combinations are: “die Angst besiegen” (to overcome fear), “eine Krankheit besiegen” (to overcome an illness), or “seine Zweifel besiegen” (to overcome one's doubts).
Mit viel Disziplin hat er seine schlechten Gewohnheiten besiegt.
With a lot of discipline, he overcame his bad habits.
to lose
'verlieren' and 'besiegen' both belong to games, competitions, or fights, but they describe different sides. Someone who 'verliert' does not win. Someone who 'besiegt' someone else is stronger and wins against that person or team. The words can be confused because they occur in the same situation. The point of view is important: you 'verliert' a game or against an opponent; you 'besiegt' an opponent.

Am Abend besiegt meine Kollegin ihren Bruder beim Schach.
In the evening, my colleague defeats her brother at chess.
Unsere Mannschaft verliert das Spiel trotz vieler guter Chancen.
Our team loses the game despite many good chances.