Pavel Avksentyev practiced at the Shuvalov swimming school at St. Petersburg. At the 1912 Olympics in Stockholm, he competed in the 400 and 1500 metres freestyle but did not finish his heats in both events. At the first All-Russian Olympics in 1913, he became the inaugural national champion in the same events as in Stockholm and placed second in the springboard diving. His times in the swimming events at were recorded as the first official Russian records in the 400 metres freestyle (7:23.8) and 1,500 metres freestyle (29:13.2)