Loch ended long World Cup barren spell as Julia Taubitz defeated returning Olympic champ Natalie Geisenberger at start of 2020-21 World Cup campaign.
Last season, the three-time Olympic gold medallist failed to record an individual triumph for the first time since making his World Cup debut midway through 2008-09.
But the 31-year-old showed he remains a potent force by claiming the men's singles opener at the Igls Sliding Centre in Innsbruck, Austria on Saturday.
It was a mighty effort from Fischnaller who has been taking antibiotics to treat appendicitis diagnosed at the start of the week.
Jonas Mueller won both races at Igls a year ago, but a disappointing first run ended his hopes of repeating that double.
The 23-year-old Austrian sent out a warning shot in the second, showing excellent speed especially at the bottom to move up from 11th to fifth.
Reigning world champion and overall World Cup winner Roman Repilov and fellow Russian Semen Pavlichenko, who won the 2018-19 World Cup, both struggled in the opener, finishing 10th and ninth respectively.
Loch then helped Germany to a narrow mixed team relay success over Austria before taking the sprint event on Sunday for a hat-trick of wins on the weekend.
Gleirscher was second, 0.088s behind, with Mueller third and Ludwig down in sixth.
Four-time Olympic gold medallist Natalie Geisenberger made her return to World Cup luge action after giving birth to her first child in May.
In her absence last season, Julia Taubitz edged out Russia's Tatiana Ivanova to claim her first series triumph.
Taubitz completed victory in Igls on Sunday morning, but Geisenberger was just 0.120s behind in second with PyeongChang silver medallist Dajana Eitberger making it a podium sweep for Germany as she also made her return from maternity leave.
Ivanova was down in 20th with team-mate Ekaterina Katnikova fourth ahead of Austria's Madeleine Egle.
It was the same 1-2-3 in the sprint with Taubitz, who was also part of Germany's mixed relay success, again getting the better of the 'sliding mums'.
She was faster than Geisenberger by 0.067s with Eitberger over a tenth further back, to claim her third win of the day.
The battle between the top two, as Geisenberger returns to top shape, should be an enthralling one for the whole of the season.
On their home track, the duo - who finished fourth at PyeongChang 2018 - won the World Cup opener by a comfortable 0.225s from compatriots Yannick Mueller and Armin Frauscher.
Russia were third in the team relay with podium hopefuls Italy disqualified when Andrea Voetter missed the paddle at the end of her run to start the next slider.
In the sprint, Eggert and Benecken got it all wrong as they lost control on Turn 11 and thankfully walking away unharmed after bumping their way to the bottom.