On their European debut Neath, also from Wales, briefly took the lead at Aaslesund when former Swansea star Lee Trundle scored a superb free-kick midway through the first half.
But goals from Lars Fuhre, Magnus Sylling Olsen, Fredrik Ulvestad and Kjell Rune Sellin gave the Norwegian side a 4-1 win.
Northern Irish side Glentoran had two men sent off as they fell to a late 2-1 defeat at Macedonia’s Renova Cepciste.
Defender Jamie McGovern was shown a straight red card after he gave away a penalty on 14 minutes, from which Boban Jancevski scored, but Colin Nixon equalised when he headed in a corner just before the break.
The visitors held on until the 87th minute but Muarem Bajrami scored a late winner, before keeper Elliott Morris was shown a second yellow card.
League of Ireland club St Patrick’s Athetlc went down 1-0 to IBV in Iceland.
Keeper Gary Rogers hauled down ex-Iceland international Tryggvi Gudmundsson five minutes into the second half and home captain Andri Olafsson calmly sent the goalkeeper the wrong way from the spot for the only goal of this first leg.