Swansea went clear at the top of Europa League Group A with a scrappy 1-0 win over St Gallen at the Liberty Stadium.
Wayne Routledge got the only goal of the game six minutes into the second half, tapping in at the far post.
Swansea were a long way short of the form they showed in humbling Valencia at the Mestalla in their first group game, and the visitors would have taken something from the game had striker Goran Karanovic converted a first-half penalty.
The game was hardly helped by the inconsistent and fussy refereeing of Duarte Gomes, but Swansea can now head into the home game with Kuban Krasnodar later this month knowing a win would make them strong favourites to claim a place in the last 32.
But St Gallen will rue failing to take their golden opportunity to cause an upset when it arrived in just the 14th minute.
Dwight Tiendalli was adjudged to have handled in the box, but Karanovic's weak spot-kick was easily saved by Gerhard Tremmel.
To add injury to insult Karanovic was removed at half-time having had no recollection of his miss after being concussed in a collision with Tremmel.
The rest of the first half was overshadowed by the lengthy running repairs administered to Michu after the forward suffered a cut to the head. He missed more than eight minutes of play and ended up getting through five shirts before the night was out.
But Routledge got the decisive strike when Wilfried Bony's shot from Alejandro Pozuelo's pass was only half saved, and the winger had the easy task of finishing.
St Gallen's 12-match unbeaten run and wins over Spartak Moscow and Kuban Krasnodar in this competition suggested they would provide the sternest test Swansea had yet faced in Europe, and so it proved.
The Swiss side looked sharp on the counter and one such rapid attack led to the penalty.
Roberto Rodriguez's cross struck Tiendalli on the arm and, although Swansea protested, it looked a fair decision from Gomes.
But Karanovic, with nine goals to his name so far this season, produced a dreadful penalty, with the stutter in his run-up ensuring his effort lacked power and Tremmel gratefully saved.
Marco Mathys also wasted a gilt-edged chance for the visitors, sliding his shot past the advancing Tremmel, but narrowly beyond the post.
Swansea responded by hitting the woodwork. Ben Davies floated over a free-kick and Daniel Lopar just about pushed Jordi Amat's header onto the post.
Michu, having already had one penalty claim rejected, then went down in the box as Stephane Besle caught him on the head.
Again no spot-kick was given, but with the Spaniard flat out on the turf having suffered a head injury, Swansea were incensed when Gomes did not stop play, as he had when Karanovic stayed down after his clash with Tremmel.
Michu got to his feet with blood streaming from a cut and a farce developed as efforts to stem the flow, including vaseline, bandages and a change of shirt, all failed.
He was then prevented from returning as blood seeped onto his change shirt, before a numberless jersey was finally deemed up to standard and he wandered back on after a full eight-and-a-half minutes off the field.
During his absence Tremmel was forced to quickly regather a Mathys shot after fumbling initially, while Bony fired narrowly wide after Swansea's best passage of play.
But Michu, now with a name and number on his jersey after a member of backroom staff was despatched to the club shop during the break, and his team-mates only had to wait six minutes into the second half for the opener as Routledge tapped in at the far post.
After the goal, Swansea finally enjoyed some semblance of control.
However, they almost had a rude awakening when Karanovic's replacement Alhassane Keita beautifully brought down a long ball and lofted over Tremmel, but also over the bar.
At the other end substitute Alvaro Vazquez, on for Bony, almost doubled Swansea's lead with his first contribution, racing clear but curling just wide.
Lopar then saved brilliantly from Dyer, before Swansea saw out a nervy period of injury time, with Stephane Netar striking the post from distance, to make it two wins from two.