PORSTMOUTH, England, Jan 11 (Reuters) - Gabriel Martinelli scored his first ‌hat-trick for Arsenal as the Premier League leaders beat second-tier strugglers Portsmouth 4-1 to reach the FA Cup fourth round ‌on Sunday.

The Brazilian was criticised in midweek for his behaviour after Liverpool's Conor Bradley suffered a serious injury near the ‌end of their Premier League clash on Thursday but ended the week in style with his first goals in the FA Cup.