Give someone a run for one's money

Give someone a good run / Give someone a hard time


Dare del filo da torcere

Fargliela sudare


Meanings
To make it difficult for someone to win by competing very well; to put up a hard struggle

Examples
Everybody knows that the reigning champ is going to win, but his opponent is very tough and I'm sure he will give him a good run
Si sa che il campione in carica vincerà, ma lo sfidante è un osso duro e sono sicuro che gli darà del filo da torcere

The Democrat won the election by a very narrow margin, the Republican candidate having given him a good run for his money
Il candidato Democratico ha vinto il ballottaggio ma solo per pochissimi voti, dato che il rappresentante Repubblicano gli ha dato molto filo da torcere

Origin
If you are betting on a horse and it doesn't win but comes close, you have lost your money, but at least had a run for it