2018 Short Course World Championships (Hangzhou, China)
Grinev was part of the 4×100 free relay team which set the European record (3:03.11 SCM) in Hangzhou. He also swam on the silver medal 4×200 free and 4×100 medley relays.
National Record in the 100 Free
At the 2019 Russian Championships in April, Grinev made headlines when he broke the 10-year-old national record in the 100 free, registering a 47.43 which was the #1 time in the world at that point in the year.
2019 World Championships (Gwangju, South Korea)
Grinev earned the bronze medal in the 100 free at the FINA World Championships in July 2019, clocking a 47.82 behind American Caeleb Dressel (46.96) and Australia’s Kyle Chalmers (47.08).
Grinev swam the leadoff leg of the Russia’s silver medal 4×100 relay at Worlds, clocking a 47.83 en route to the team’s 3:09.97. Vladimir Morozov, Kliment Kolesnikov and Evgeny Rylov rounded out the lineup, which finished 91 hundredths of a second behind the gold medal team from the United States (3:09.06). Grinev also swam on the prelims of the 4×100 medley relay, splitting 47.20 in the morning. Russia ended up earning a silver medal in the final.