Roger Federer has revealed that he was disappointed with his performance during his win over Adrian Ungur in the second round of the French Open.

The world number three sealed a record 234th victory in a Grand Slam when he saw off the Romanian 6-3 6-2 6-7 6-3 at Roland Garros on Wednesday.

However, the 30-year-old believes that he gave his opponent too many opportunities during the contest.

"Instead of being aggressive I let him show me what he could do," Federer told reporters. "He played two beautiful shots and he played very well."

The 16-time Grand Slam winner will face France's Nicolas Mahut in the next round.