Don't mention the B word.
That is probably the view of both Arsenal and Manchester United ahead of Friday's Champions League quarter-final draw.
Having been so comprehensively defeated by Barcelona in last season's final, United know all about the threat of Pep Guardiola's men.
Sir Alex Ferguson might have raised a few quizzical looks at the start of the season when he named the Catalans as the major threat to his own side's hopes of regaining their crown - and ignored Real Madrid completely.
But, not for the first time, Ferguson's opinion has proved to be astute. Real fell at the last-16 stage again and no-one who saw Barcelona dismantle Stuttgart, with a couple of goals from the brilliant Lionel Messi included in the rout, would face them with any degree of confidence.
Having encountered Barca with much more success at the semi-final stage two seasons ago, United could argue it is someone else's turn to face them.
Not that Arsenal are without previous. Four years ago it appeared the Gunners were about to land the most coveted trophy in club football for the first time, only for Samuel Eto'o and current Chelsea star Juliano Belletti to score in the final 15 minutes to shatter Arsene Wenger's dream.
After Tuesday night's events at Stamford Bridge, Inter Milan will be treated with only slightly less caution.
What Jose Mourinho's team lack in flamboyance, they make up for in organisation.
Walter Samuel and Lucio are a formidable central defensive partnership, as Didier Drogba discovered. Lucio's absence from the first leg of the quarter-final is a huge blow and the fact his three defensive colleagues are all one caution away from a ban is a point of weakness.
Still, the media at least would welcome another visit from Mourinho, beaten by Ferguson's United at the last 16 stage 12 months ago but seemingly far better prepared to end that 45-year wait to lift the European Cup.
An all-English last eight meeting is a possibility too.
Wenger has said he wouldn't mind that, despite suffering successive home hammerings at United's hands, including last season's semi-final when Arsenal were blitzed, never recovering from conceding two goals in the opening 11 minutes at the Emirates having trailed by just a single goal from the first leg.
If Barcelona, Inter, and the English club's respective domestic rivals themselves represent the biggest threat, another danger lurks in the scheduling.
Unless they are drawn against each other, one of the title-chasing duo will end up playing their first leg on Wednesday, March 31 with the second the following Tuesday, and a league game in between.
The presence of CSKA Moscow in the last eight therefore creates the potential for a draining return trip to Russia, followed, less than 60 hours later by a game that could be pivotal to the championship.
For Arsenal, who have a chronic record in Russia anyway, the fixture in question is against relegation scrappers Wolves at home, for United, it is against Chelsea. The consequences of this will not be lost on Ferguson.
Bayern Munich - famously beaten by United in the 1999 final - are flexing their muscles once more and disposed of Fiorentina easily enough in the first knockout round, so they deserve respect.
The same is also true of French duo Lyon - who caused the biggest shock in the competition so far by knocking out Real - and a progressive Bordeaux side coached by former United defender Laurent Blanc, who is being tipped in some quarters as an eventual successor to Ferguson.
Like Arsenal, Lyon, Bordeaux and CSKA Moscow have never won Europe's most prestigious competition.
To end that drought someone will have to beat Barcelona. It is going to be a tough task.
The draw is being held in Nyon at 11am tomorrow (GMT).
