Arsenal manager Arsene Wenger believes the demands of the Premier League caught up with England's four clubs in the Champions League this week.

His injury-hit side failed to score in a stalemate with Fenerbahce on Wednesday while Manchester United needed a late equaliser to draw 1-1 with Celtic.

Premier League leaders Chelsea lost 3-1 at Roma on Tuesday when Liverpool escaped with a 1-1 draw against Atletico Madrid at Anfield thanks to a dubious stoppage-time penalty converted by Steven Gerrard.

"Look at all the results of the English teams this week," Wenger told reporters after their draw in Group G.

"Until this week none of the four had lost this season in the Champions League and this week none of them won.

"I watched Liverpool and they drew, I'm not sure how, Chelsea were not sharp physically, we were not sharp physically and it looks like the Premier League is very demanding physically.

"If you have a Premier League week and Champions League week after it is difficult."

Arsenal faded badly against a defensive Fenerbahce side and barely mustered a chance in the second half as their hopes of an early passage into the last 16 were dashed.

Four days earlier, Wenger's side were overpowered 2-1 in the league at Stoke City, leading to accusations that his players were being injured deliberately by opposing players.

The Premier League appears particularly tough this season with all three promoted sides proving tough opponents.

United were pushed all the way in a 4-3 win over Hull City on Saturday at Old Trafford while Arsenal have already lost to Hull as well as Stoke and regular strugglers Fulham.

Wenger refused to backtrack on his comments about Stoke's players earlier in the week, adding that he felt his team were unfairly treated by referees.

"We are top of the fair play table, we make fewer fouls than any other club in the Premier League," he said.

"But you look at the teams that get the most yellow cards after four or five fouls it is Arsenal. Some get their first yellow after 15 fouls.

"Either I need to go back and read the book, or something is wrong."

Next up for Arsenal is a clash with champions United at the Emirates tomorrow and they know another league defeat would leave them well adrift in the title race.

"It's a massive game, very important for us," Wenger said.