St Johnstone pulled off a shock in Norway, as defender Frazer Wright's first-half goal proved enough to beat Rosenborg 1-0 on Thursday night.
The centre-half made the most of a brief period of Saints pressure in the opening stages to net from close range and secure his side a precious away goal.
But there were worrying moments following Wright's 19th-minute strike and Tommy Wright's team were forced to defend stoutly to protect their lead.
The Perth side's goalkeeper Alan Mannus in particular did his best to ensure the clean-sheet was guarded as he pulled off a string of important saves in the minutes following the start of the second-half.
St Johnstone will now hope to complete a remarkable victory when they host the 22-time Norwegian champions in the return leg at McDiarmid Park next Thursday.
However, Hibernian face an uphill task to keep their Europa League campaign going after they lost 2-0 to Swedish league leaders Malmo.
First-half goals from skipper Jiloan Hamad and Magnus Eriksson, just two minutes apart, ensured the Easter Road team were forced to endure a long evening at Swedbank Stadion.
The visitors face a tough return back in Edinburgh next Thursday against a team whose greater sharpness and fitness from being almost midway through their domestic season was clearly evident.
Aaron Burns' strike secured Linfield a famous Europa League win against Xanthi in Greece.
Blues manager David Jeffrey had admitted concerns over the heat's impact on his players in the build-up to the second qualifying round first leg.
However, the Northern Irish side faced similar energy-sapping conditions against AEL Limassol in last season's Champions League and had clearly learned from that experience.
Burns grabbed the winner in just the 25th minute, firing past Christian Gimenez after good work down the left.
Xanthi enjoyed the lion's share of possession after the goal, but Linfield held on to take a 1-0 lead into next week's second leg at Windsor Park.
Derry were another to impress in Europe as they gave Trabzonspor a scare.
Adrian Mierzejewski and Paulo Henrique efforts gave the Turkish side a two-goal lead within 16 minutes, only for City to come storming back.
David McDaid pulled one back at the Huseyin Avni Aker Stadium, before Patrick Kavanagh drew parity in the 32nd minute.
It had looked like another shock could be on the cards, only for an own goal from captain Barry Molloy to put Derry on the back foot before half-time.
Giray Kacar put Trabzonspor further ahead early in the second half but City continued to threaten, with Ryan McBride firing just wide in injury time as the match finished 4-2 to the hosts.
Prestatyn Town's task next week looks nigh on impossible after suffering a 5-0 hammering in Croatia.
Rijeka came into the match as overwhelming favourites and did not disappoint, with former international Leon Benko netting a hat-trick before Vedran Jugovic and Damir Zlomislic added gloss to the scoreline.