The 2016 Rio Olympic Swimming events kicked off with a bang this weekend. United States swimmers excelled in certain events, while reigning champ Dana Vollmer met her match from Sweden — Sarah Sjöström. Australia created a strong current in the stream of competitors, taking top spots in both relay and individual events. The team's preeminence even spurred some heated competition between Australian swimmer Mack Horton and Chinese swimmer Sun Yang. Swimmers from various countries smashed previous Olympic and world records and earned their first gold medals, already making this Olympics one to remember even in the first two days of competition. Here are the highlights from this weekend incase you missed these riveting results.

Men's Events

Men's 100m backstroke

The U.S. team dominated the 100m backstroke semis as Ryan Murphy and David Plummer both placed first in both heats. Murphy's and Plummer's success create a high probability for at least one U.S. athlete to medal in this event.

Men's 100m Breaststroke

Adam Peaty from Great Britain set a world record in the prelims with a time of 57.62 and outdid this time in finals with a time of 57.13, leading the pack by about a second. South African swimmer Cameron van der Burgh and U.S. swimmer Cody Miller took the silver and bronze medals.

Men's 200m Freestyle

Chinese swimmer Sun Yang and U.S. swimmer Conor Dwyer took first in the two semis heats. Japanese swimmer Kosuke Hagino and German swimmer Paul Biedermann took second in these heats with solid times, but it appears that Yang may ultimately take the gold in this event considering his solid finish in the 400m freestyle.

Men's 400m Individual Medley

Kosuke Hagino from Japan took first in this event, narrowly taking the gold with a time of 4:06.05, less than a second in front of silver medalist Chase Kalisz from the U.S. team. Japan earned a second medal in this event with Daiya Seto earning the bronze medal. The United States set a gold medal streak, maintained by Ryan Lochte in 2012, but Kalisz came slightly short of earning gold in this event.

Men's 400m freestyle relay *

Four talented U.S. men — Caeleb Dressel, Michael Phelps, Ryan Held, and Nathan Adrian — all contributed to a phenomenal finish and a gold medal for the U.S. in this event with a time of 3:09.12. Dressel made a solid Olympic debut with his opening 100 building a sturdy foundation for his team. Longtime and heavily decorated Olympic veteran Michael Phelps continued his powerful momentum and stroked ahead of the pack, setting up a potential win only halfway through the race. Phelps was not solely responsible for the team's success, however, and each individual greatly contributed their hard work. Held rose to the challenge in the third 100 and freestyle sprinter Adrian anchored the last 400, clinching a gold medal for the U.S. Phelps added his 19th gold medal and 23rd Olympic career medal to his vast collection from this race while Dressel and Held acquired their first Olympic gold medals. France and Australia earned the silver and bronze medals in this relay.

Men's 400m freestyle

Australia came up from Down Under and rose to the surface this opening weekend, a trend the team continues throughout various men's and women's swimming events. Mack Horton from Australia and Sun Yang from China stood neck and neck in this race, but Horton took the gold in this event with a time of 3:41.55. Gabriele Detti from Italy took bronze, 1.81 seconds behind Yang.

Women's Events

Women's 100m Backstroke

The semifinals took place this opening weekend and finals commence Monday evening. Hungarian swimmer Katinka Hosszu swam an impressive IM earlier in the weekend, but U.S. swimmer Kathleen Baker ousted her in this event by a tenth of a second.

Women's 100m Breaststroke

Another U.S. swimmer, Lilly King, topped the competition in her semi finals heat, but Russian swimmer Yulia Efimova earned almost the exact same time as King with less than a tenth of a second difference between their times. King and Efimova will face off Monday night for the gold during the breaststroke finals. U.S. swimmer Kate Meili additionally took third in the same heat as King and could potentially earn a bronze medal in this event.

Women's 100m Butterfly

Dana Vollmer took the gold in this event with a time of 55.98 back at the 2012 Olympics and became the first woman to swim this particular event in under 56 seconds, but Sarah Sjöström from Sweden broke her world record at the 2015 World Championships. Sjöström shone again in the semi finals, breaking Vollmer's Olympic record with a time of 55.84. She put up a fiercer fight in finals and broke her own record again with a time of 55.48, taking the gold while Penny Oleksiak from Canada earned a silver medal. Vollmer swam a steady race and gained a bronze medal but failed to match the record she set in London four years ago.

Women's 400 Individual Medley

The women's 400 IM was simply astounding. Katinka Hosszu took first in this event at the 2015 World Championships. Her success directly led to a gold medal victory at with an overwhelming lead over the remaining seven swimmers, breaking Chinese swimmer Ye Shiwen's world record of 4:28.43 with a time of 4:26.36 and keeping a five second lead over silver medalist Maya Dirado. This is additionally an astounding accomplishment considering her husband doubles as her coach.

Women's 400 freestyle relay

Australia took first in the finals and broke the world record with a time of 3:30.65. The United States started with a clear lead by Simone Manuel and Abby Wietziel, but Bronte Campbell inched ahead of Dana Vollmer in the third 100, allowing Australia to gain a large lead over the U.S. Cate Campbellmaintained her lead and stayed ahead of Katie Ledecky. The U.S. women still swam hard despite Australia's firm lead and earned silver medals.

Women's 400 Freestyle

Katie Ledecky shone four years ago during the London Olympics and killed it once again this year when she earned her first gold medal this Olympics and set a world record with a time of 3:56.46 in the 400 freestyle. The other competitors proved no challenge for the skilled swimmer, who upheld a five second lead over silver medalist Jazmin Carlin from Great Britain. Ledecky swam this event back in 2012, earning third with a time of 4:05.00, and beat this record by approximately nine seconds.