As a result of three consecutive unexpected wins, European League of Legends casters referred to today as "Upset Day." Before this week, most matches between bottom four and top six teams have been easy to predict with few bottom four teams stealing wins from top six teams.

A great deal of these upsets came in the context of teamfights or reactions to aggressive plays. One player on a top six team found himself caught out or didn't particularly appreciate the interaction between two different champions in a team fight. This week saw the rise of Sivir and Azir, and Shurima changes the pace of 5v5s.

Trundle-Gragas and the scaling Ezreal

Things began to go awry for Fnatic before the eight-minute mark. A flanking dive from Berk "Gilius" Demir resulted in 4 kills for 2. In this first dive, Etienne "Steve" Michels demonstrated a smart use of Pillar of Ice to split Fnatic and isolate part of their team under turret. Gilius followed up with crowd control from Body Slam, making targets easy for Rasmus "MrRalleZ" Skinneholm to pick off. The late game scaling potential of Ezreal ensured Elements could have a late game edge, despite their historically disoriented teamfights.

The strength of Elements' team fight came from the ability of the composition to isolate and kite targets. Though Jérémy "Eika" Valdenaire had a relatively low kill participation, Lissandra's dive and Frozen Tomb creates terrain that splits targets. Gragas and Trudle can also both split fights. Following this, Alistar creates crowd control for MrRalleZ's Ezreal to slowly kite targets to death.

With Elements' composition, you don't have to take a team of five on at once. A team with less clear calls can take advantage of clearly isolating a target at a time. Elements used this to snowball their lead and continue to win fights against Fnatic. Without an advantage, Fnatic had less of an ability to set up their Azir and use it to pick fights with pre-planted Sand Soldiers.

Sivir and the instant team fight

I've bemoaned H2K-Gaming's scattered team fighting before today. Unicorns of Love demonstrated how to take advantage of it in the mid and late games.

Trundle again appeared as a counter to Poppy. Picking Trundle into Poppy slows down Poppy's ability to get into fights and counter-acts her tankiness. Trundle also split-pushes effectively against Poppy later, making it difficult to just full-on avoid a 5v5 with a Poppy and a Trundle.

The real strength of Unicorns of Love's composition came from Lissandra and Sivir. This combination has seen popularity in other leagues. Sivir's On the Hunt allows Lissandra to get into a fight more easily and set up an engagement. It's difficult to react effectively to this combination, as Sivir seems to make everything happen so quickly. The Lissandra-Sivir duo took advantage of some of H2K's trickier lane assignments with Konstantinos "FORG1VEN" Tzortziou-Napoleon split-pushing a side lane on his own or positioning as a front liner in team fights.

Even beyond the Lissandra and Sivir duo, H2K demonstrated difficulty with team fighting. Andrei "Odoamne" Pascu took a couple engages without follow-up from his team. In some instances, these fights could have gone well for H2K, but Odoamne's health bar simply disappeared without backup. Other times — an engagement in the first place may not have been ideal. H2K need to make a decision on how to handle these sudden engagements, and a flaw in their team fighting may be in the way their communication works at the start of a scramble.

H2K have often been characterized as the team that avoids fights and so doesn't need to know how to execute them. It's a very rare game that doesn't require any fighting whatsoever. As a result, teams that acquire leads strategically should at least understand passable team fighting technique for closing purposes or for coming back into the game if something in the early game should go wrong.

Vitality and the unforgivable Sivir loss

The desk today already criticized Vitality's Sivir composition. When drafting Sivir, one should consider picking multiple forms of hard engage. Vitality's Sivir only benefited the Poppy and lacked another form of collapse like the Lissandra used by Unicorns of Love.

Vitality drafted Leblanc to deal with the Azir, and to Erlend "Nukeduck" Våtevik Holm's credit, he had a rare death-less game. When it comes to team fighting, compositions require cohesion. Vitality have drafted creative combinations in the past, such as Zilean and Bard or their impressive Kog'Maw composition with Tahm Kench and high mobility. This game lacked unity and champions that worked well together.

As a result, Vitality seemed to scatter much more often. This created opportunities for Erik "Tabzz" van Helvert's Jhin to find picks. ROCCAT's composition, even with the Renekton selection, created opportunities for Azir and Jhin to set up for fights as top, jungle, and support stalled with crowd control. In the late game, when Vitality began to play more and more panicked, this worked to their advantage, and ROCCAT found crucial picks to close the game.

To hammer in the point, today's upsets created an opportunity for G2 Esports, a team that often drafts for team fighting cohesion, to secure a top two berth in the European League of Legends Championship Series playoffs. Barring a loss by G2 tomorrow, they should take first place in the regular season. Teamfighting has strategic elements to it, and it's important that team fight synergy and win conditions are not ignored for even the least confrontational team to win games. Of Europe's top five teams, G2 had the firmest grasp of this concept today and took home the reward.

Kelsey Moser is a staff writer for theScore esports. You can follow her on Twitter.