In what was their first-ever appearance in the A-Division of the European Curling Championships, Turkey's women recorded a historic win by defeating Russia's defending champions 7-6.
The game on the first day of play at the Championships in St Gallen, Switzerland, was tight all the way but a score of three points by Turkey in the seventh end made all the difference at the Eissportzentrum Lerchenfeld.
In the same session, Sweden and Scotland - the silver and bronze medallists from 2016 and represented in St Gallen by the teams that will compete at the Pyeongchang 2018 Winter Olympics - faced each other.
This game also turned on a score of three points.
After four blank ends, Sweden finally got onto the scoreboard in the fifth end when their skip Anna Hasselborg drew her last stone into the house for three points.
Sweden went on to win by 5-2.
Hosts Switzerland - whose athletes have been selected for the impending Winter Olympics - earned a 9-4 opening round robin win over Denmark.
Sweden's men made a strong start to their defence of the title as they registered victories in both of their sessions.
The Swedes began with a 10-6 round robin win over Austria and then beat Germany 8-2 to finish the day, sharing top spot with Scotland and the hosts.
Scotland beat Italy 7-3 in their first match before defeating Austria by the same score in their evening match, while Switzerland earned an 8-3 win over The Netherlands and an 8-6 win over Norway.
The latter game was the only one of the evening session to complete ten ends, with the hosts’ fourth player, Benoit Schwartz, hitting out a Norway stone to complete victory.
Scotland's skip, Kyle Smith, said: "It's the perfect start really.
"We've executed well today, so we're very pleased.
"We started with hammer in both games, which always helps - so we've made a good job of the draw shots.
"We have put stones in the right place, thrown to the sweepers and adapted to the ice well."