McManus was the alternate for the Swedish team at the 2009 and 2010 World Junior Curling Championships. The team, which was skipped by Anna Hasselborg finished in sixth place in 2009 and won the gold medal in 2010. While McManus was listed as an alternate, the team acted as a five-player team, with McManus throwing lead rocks in most of the team's games. The team was taken over by McManus' sister Jonna as skip for the 2011 World Junior Curling Championships where the team placed fourth, with Sara throwing third stones. Sara took over the team as skip for the 2012 and 2013 World Junior Curling Championships respectively. In 2012, she led her team of Anna Huhta, Marina Stener and Sofia Mabergs to a 6-3 round robin finish, which put them in a four-way tie for 3rd place. The team won their tiebreak match against Japan, and their next playoff game against Russia. However, they lost in the semifinal to the Czech Republic and in the bronze medal game in a re-match with the Russians, finishing in fourth place. At the 2013 Juniors, McManus again skipped the Swedish junior team with Mabergs and a new front-end of Rosalie Egli and Malin Ekholm. She led the team to a 5-4 round robin record, again in a four-way tie for third place. The team then lost to the Russians in a tiebreak, finishing 5th place overall. McManus skipped the University of Gävle team, representing Sweden at the 2015 Winter Universiade. There, she led her team of Cecilia Östlund, Huhta and Mabergs to a 7-2 round robin record, in a tie for second place with Russia. However, in the playoffs they lost to Russia in the semifinal and then Switzerland in the bronze medal game, finishing in fourth place. McManus was invited to be the alternate on the Swedish team at the 2014 Ford World Women's Curling Championship. The team, which was skipped by Margaretha Sigfridsson, ended up losing the tiebreaker to South Korea, finishing in 5th place. McManus did not play in any games. McManus would again be the alternate at team Sweden, this time at the 2014 European Curling Championships, on a team skipped by Anna Hasselborg. The team finished fifth with McManus again not playing in any games. McManus was invited to play second for the Sigfridsson rink which was representing Sweden at the 2015 World Women's Curling Championship. The team finished in 7th place, missing the playoffs with a 5-6 round robin record. In the following season McManus joined the Hasselborg rink as the third, with the rink representing Sweden at the 2016 European Curling Championships. After finishing the round robin in second place with an 8-2 record, the team won their semifinal match against the Czechs before losing in the final against Russia's Viktoriia Moiseeva rink, earning the team silver medals. The rink represented Sweden again later in the season at the 2017 World Women's Curling Championship where they came just short of winning a medal finishing in fourth. The next season, the team made it all the way to the final of the 2018 World Women's Curling Championship before losing to Canada's Jennifer Jones. Team Hasselborg won back-to-back Grand Slam events at the start of the 2018-19 season, the Elite 10 and the Masters. The team lost once again the final of the World Women's Curling Championship, this year to Silvana Tirinzoni and Switzerland. Team Hasselborg began the 2019–20 season at the Stu Sells Oakville Tankard where they defeated Anna Sidorova in the final. They missed the playoffs at the 2019 AMJ Campbell Shorty Jenkins Classic after going 2–2 in the round robin. They defended their title at the 2019 European Curling Championships. Down 4–3 in the tenth end of the final to Scotland's Eve Muirhead, Hasselborg made a runback on her final stone to score two and win. In Grand Slam play, Team Hasselborg were the most dominant team on the women's side, winning them the 2019–20 Pinty's Cup. They lost in the semifinal of the Masters to Tracy Fleury before winning the next three Slams, the Tour Challenge, National and the Canadian Open. The team was set to represent Sweden at the 2020 World Women's Curling Championship before the event got cancelled due to the COVID-19 pandemic. The Canadian Open would be their last event of the season as both the Players' Championship and the Champions Cup Grand Slam events were also cancelled due to the pandemic.
