On April 2, Cristiano Ronaldo gave a praiseworthy performance, taking Manchester United to a 3-0 win against Brentford. After converting a penalty, he now stands at 18 goals in the English Premier League. A viral video on the Internet shows Ronaldo saying something to the camera after the match. Amidst the sound of the cheering crowd, it is not clear what the 37-year-old said in the video. 
However, fans and media alike have claimed that the Portuguese said "I'm not finished", implying that he is yet to retire as some were speculating. News websites such as Zee News, WION and The Telegraph UK did stories on this.

Fans have also started celebrating his statement, as evident from many Twitter posts, such as Tweets by @mrfc100 and @EmmaHam41.

Fact Check

On an Instagram post by the handle @ronaldo7club, the same claim was made: "Cristiano Ronaldo to the Camera right at the end of the match: "I'm not finished"." In a reply to this post, Ronaldo himself replied from his handle @cristiano, denying any such claims: "I didn't say that."

The unclear statement that the player gave to a camera cannot be considered as what is being claimed by the media and fans. It is not clear what the actual statement is, but Ronaldo seems to be denying the viral claims.

In conclusion, no, Ronaldo did not say "I'm not finished" at the end of Man Utd's match against Brentford. What he actually said is yet to be revealed, but the viral claims have been denied by Cristiano Ronaldo in a reply to an Instagram fan page.