The most contentious views of Arsene Wenger are no longer restricted to south-west London. He had spent last week as Jose Mourinho's plaything, the Chelsea manager opening up the Frenchman's record for debate and then lobbing a grenade inside.

Mourinho then watched from a safe distance as the whole thing caused ructions in the English game.

Typically, the debris would be scattered across the back pages, including a soundbite identifying Wenger as a "specialist in failure". That would be added to yesterday by claims made in a Scouse accent after Wenger's Arsenal side escaped past Liverpool and into the quarter-finals of the FA Cup. The London side scored twice but would be fortunate to avoid conceding a second penalty under increasing pressure.

Liverpool fans would be forgiven for referring to Wenger as less of an escape artist and more a right jammy sod. One would be tempted to tell them to focus on the league instead and just calm down, though that does seldom seems appropriate.

Their ire was more effectively contained to the away end inside the Emirates Stadium. It was from there that supporters launched their appeal for a penalty after Luis Suarez was sent sprawling inside the penalty area by a clumsy challenge from Arsenal's Alex Oxlade-Chamberlain.

The Liverpool striker has cultivated a reputation for going down easily and the heavy nudge he received in the second half elicited a similar response to a gunshot from 10 paces. Yet it remains true that it was a foul and referee Howard Webb - who will attend the World Cup finals this summer - failed to spot it.

"I thought that was quite an easy decision for the ref," said Brendan Rodgers, the Liverpool manager, who will contact the FA and ask for an official explanation for the decision not to award a penalty. "Luis has a touch, gets around him and it looks a blatant penalty. We're bitterly disappointed to have not got that because then it just keeps our momentum going for the final stages of the game."

The Anfield side had made strides in the second half. They had taken their first steps in the fifth-round cup tie with all the authority of Bambi at Sochi. Oxlade-Chamberlain steered in an opening goal for the home side after 16 minutes when he collected a fugitive ball inside the penalty area, with Liverpool's early attacks both eager and lacking poise.

Daniel Sturridge whipped a shot into the side netting and drilled another one against a trailing leg. His side was then tripped up again just two minutes after the break as Oxlade-Chamberlain charged in behind the Liverpool defence and cut a pass back for Lukas Podolski to prod a second goal past goalkeeper Brad Jones.

Podolski's next kick was far less profitable - the German clipping Suarez in the box to concede a penalty which Steven Gerrard converted. The striker would turn expectantly to Webb when he was toppled by a challenge by Oxlade-Chamberlain.

"I rate Suarez as a player," said Wenger, who dropped striker Olivier Giroud amid claims he has admitted to perpetrating an alleged affair while travelling with the team. "If we had him in the team we'd have a few more free-kicks. But it's always difficult to know with him: was it really genuine contact? It was contact, I don't deny that, but he's very good to make more of it every time."

This was managerspeak for 'take that, Liverpool'. Their fans response would be just as easy to decipher.