"I was next to Zaid bin Arqam when he was asked: 'How many battles did the Prophet (ﷺ) fight ?' He said: 'Nineteen.' So I said: 'How many battles did you take part in with him ?' he said: 'Seventeen.' I said: 'Which of them was the first?' He said: 'Dhat Al-Ushaira' or Al-'Usaira'. '"

This Hadith is Hasan Sahih.

Jami` at-Tirmidhi Book 23, Hadith 7