Barcelona dominated Arsenal to win 3-1 last night - 4-3 on aggregate - though the losers were left seething at the second-half dismissal of Dutch star Robin van Persie for a second bookable offence when he shot at goal after the referee had already blown his whistle.
Barca's goals came from a double by Lionel Messi and one from Xavi while the Gunners sole reply was a Sergi Busquets own goal in a match where the losers might feel aggrieved but the statistic of 19 shots by the hosts, with 10 on target, to Arsenal's zero tells its own story.
Shakhtar eased through 3-0 at home to Roma for a 6-2 aggregate victory - the Italians played for 50 minutes with 10 players after French central defender Philippe Mexes was also dismissed for a second bookable offence.
Roma were fortunate not to also see Daniele De Rossi get a straight red card for a vicious elbow on Shakhtar captain Dario Srna on the stroke of half-time - England's World Cup final referee Howard Webb ended up booking a bemused Srna instead.
Shakhtar's victory - which confirmed they are a force to be reckoned with by most teams left in the competition - will be keenly felt by Arsenal as well.
Not only did former Gunners striker Eduardo get among the goals for the Ukrainian side in Tuesday's win but Arsenal demolished them 5-1 in the group stage at the Emirates only to end up second to the 2009 UEFA Cup winners in the final standings.
Barcelona coach Pep Guardiola admitted it had been a tough decision by Swiss referee Massimo Busacca to book Van Persie for the second offence but he had no truc with Arsenal''s unlucky losers claim.
"We didn't allow them to make three or four successive passes this evening. We played a perfect game. I am so happy, indeed we all are at our performance. Over the two legs we were better than them,"he said.