Caeleb Dressel Fires Off 49.33 100 Butterfly Split in Mixed Medley Relay


Swimming in the final of the 4 x 100 mixed medley relay, American Caeleb Dressel posted a 49.33 butterfly split to give the United States a 1.25-second lead over Australia going into freestyle. Though the Americans did not defend their 2017 title, Dressel’s split in the butterfly deserves recognition, and could preview his individual 100 fly times Friday and Saturday.

Dressel’s 49.76 relay split in 2017 was the second-fastest all-time behind only Michael Phelps‘ 49.72 relay split from the 2009 World Championships in Rome, and the fastest split ever in a textile suit. Based on previous FINA record keeping practices, Dressel’s split today may not “officially” count as the fastest all-time, but we’re not going to forget it anytime soon.

To the best of our knowledge, Dressel and Phelps are the only swimmers in history to produce sub-50 splits in the 100 LCM butterfly in the medley relay, mixed or traditional. To date, Dressel has registered three 49-second splits and Phelps one. Chad le Clos is the third-fastest on the medley relay with a 50.10 fly split from the men’s 400 medley relay at the 2018 Commonwealth Games with a 50.10.

Fastest Butterfly Splits in Medley Relay History:

Rank Swimmer Time Country Event Competition
1 Caeleb Dressel 49.33 United States Mixed 400 Medley Relay 2019 World Championships
2 Michael Phelps 49.72 United States Men’s 400 Medley Relay 2009 World Championships
3 Caeleb Dressel 49.76 United States Men’s 400 Medley Relay 2017 World Championships
4 Caeleb Dressel 49.92 United States Mixed 400 Medley Relay 2017 World Championships
5 Chad le Clos 50.10 South Africa Men’s 400 Medley Relay 2018 Commonwealth Games
6 Michael Phelps 50.15 United States Men’s 400 Medley Relay 2008 Beijing Olympic Games
7 Andrew Lauterstein 50.16 Australia Men’s 400 Medley Relay 2009 World Championships
7 Gabriel Mangabeira 50.16 Brazil Men’s 400 Medley Relay 2009 World Championships

Dressel Split Comparison:Dressel’s reaction time today was a relatively quick .28, unlike 2017 where he was off the blocks in a .42, the slowest in the field. At the 2017 World Championships, Dressel teased fans with a 49.92 butterfly split in the finals of the mixed medley relay, which the United States won in World Record fashion. Dressel then fired off a 50.08 in the prelims of the 100 fly, a 50.07 in the semifinals, and a 49.86 in the finals, missing Phelps’ World Record by only .04. Dressel ended the meet with a 49.76 butterfly split in the men’s 400 medley relay.

Race: 2017 Mixed Medley Relay 2017 100 Fly Final – Flat Start 2017 Men’s Medley Relay 2018 Mixed Medley Relay
Split: 49.92 49.86 49.76 49.33

If we were to predict Dressel’s time in the finals of the 100 fly based off the information we have from the 2017 World Championships, supposing he drops another .10 from his relay split to his flat start, Dressel’s finals time would be a 49.23. That is an unbelievably fast time, but it’s worth remembering that he went 50.36 unrested in June.

Whatever Dressel goes in the 100 fly, it’s sure to be faster than 50.00, and he may not be the only swimmer sub-50. After watching 19-year-old Hungarian Kristof Milak destroy Phelps’ 200 fly World Record with a 1:50.73, it’s reasonable to predict that Milak also slips under 50 and the current World Record of 49.82 in the 100 fly. Milak’s best time is 50.62 from the 2017 World Championships where the then-17-year-old took 2nd to Dressel.

To date, only Michael Phelps (49.82), Caeleb Dressel (49.86), and Serbia’s Milorad Cavic (49.95) have been under 50 seconds in the 100 LCM butterfly, and each swimmer has only done it (flat start) on one occasion.

Other notable splits in the Mixed medley relay include Russia’s Evgeny Rylov‘s 51.97 backstroke lead-off and Cate Campbell‘s 51.10 freestyle anchor leg that propelled the Australian team to gold over the United States.

One note on Phelps’ 2009 World Record in the 200 fly: Though Phelps’ swam the time at the 2009 World Championships in Rome, it is worth noting that he did not wear a full-body suit for the race and opted only for the Speedo LZR Racer legskins with polyurethane paneling.


  • World Record: United States (Grevers, King, Dressel, Manuel), 2017, 3:38.56
  • World Junior Record: Russia (Prikhodko, Chupkov, Pakhomov, Openysheva), 2015, 3:45.85
  • World Championships Record: United States (Grevers, King, Dressel, Manuel), 2017, 3:38.56
  • 2017 Defending World Champions: United States (Grevers, King, Dressel, Manuel), 2017, 3:38.56


  • GOLD: Australia (Larkin, Wilson, McKeon, Campbell), 3:39.08
  • SILVER: United States (Murphy, King, Dressel, Manuel), 3:39.10
  • BRONZE: Great Britain (Davies, Peaty, Guy, Anderson), 3:40.68

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Dressel wins it in finals but if he holds back in prelims and semis Milak could beat him to the record. Dressel still shatters it in finals.

Justin Thompson

Pump the brakes, Milak will go 50.25 at best.


After a 1:50.7 I’m not doubting him of anything this week


And the 1.25 second lead he gave anchor over Australia still wasnt enough…bummer. so much for 8 golds


you gotta look at the 1st leg…Ryan Murphy split a pedestrian (by his standards) 52.46…USA needed something better than 52.3 there. Then, if they didn’t get it there, if they got just a 1:04.8 or better from Lily (although I’d argue this was probably the best she was going to ever go at this meet…), and Simone split faster in the regular 400 free relay instead of 52.37. I think 3 of 4 legs could’ve been slightly quicker to have switched USA and Australia…however, it was a very fun race to watch and as an American, I look forward to seeing the rematch at the Olympics…one thing I would love to see is the USA (maybe for fun at a… Read more »


I think the exchanges were a bit conservative for a bunch of NCAA veterans they should cut it a little closer.


Some of the finishes were long, especially King’s. Not ideal for fast relay exchanges.


I mean Mitch Larkin swam pretty damn so slow so the US kinda should’ve won it


Yeah, everybody but Dressel left just a little bit on the table, and the Australians, particularly Campbell, capitalized.


“It’s reasonable to predict that Milak also slips under 50 and the current World Record of 49.82 in the 100 fly” – I’m not sure about this. It doesn’t always work like that.


Fax. It’s not like Chupkov can break Adam Peaty’s world record.

About Reid Carlson

Reid Carlson

Reid Carlson originally hails from Clay Center, Kansas, where he began swimming at age six.  At age 14 he began swimming club year-round and later with his high school team, making state all four years.  He was fortunate enough to draw the attention of Kalamazoo College where he went on to …

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