Manchester - Manchester United will attempt to end Benfica's unbeaten start to the season on Tuesday as the English club bid to book their place in the Champions League knockout phase.
The English and Portuguese giants play out the latest instalment of a decades-old rivalry at Old Trafford knowing that a win for either side will almost certainly assure them of topping Group C.
United had to come from behind to snatch a 1-1 draw in the two teams' meeting in Lisbon earlier in the group, and Benfica remain unbeaten in 20 matches across all competitions this year.
United, who famously defeated Benfica at Wembley in 1968 to win their first European crown, head into the tie on the back of five straight victories.
Significantly, those five wins have all been matched by five cleansheets, a fact that signals United's defence is on the mend after being torn apart by Manchester City last month.
"Keeping clean sheets has been an integral part of our success and we have been careless with our defending," United manager Sir Alex Ferguson said after watching his team score a 1-0 victory over Swansea last weekend.
Ferguson said the win over Swansea reflected a focus that had been missing from United's early games this season.
"The concentration we showed is exactly the concentration we need back in the team," he said.
While United's defence is causing him fewer sleepless nights, it remains to be seen how Ferguson will set up his midfield against Benfica.
Against Romanian side Otelul Galati earlier this month, Ferguson used Wayne Rooney as a central midfielder to great effect.
Yet while Rooney won plaudits for his performance, it merely served to underscore United's lack of a genuine creative presence capable of running the game from midfield.
According to Scottish international Darren Fletcher, United are doomed to failure in their attempts to find a midfielder capable of replacing the now retired Paul Scholes.
"We can't replace Paul Scholes, it is as simple as that," Fletcher said. "If there was someone I am sure he would be here.
"You are talking about one of the best players ever to play for Manchester United."
Ferguson will instead have to perm the core of his midfield from Ryan Giggs, Michael Carrick, Park Ji-Sung and Fletcher.
Fletcher believes, however, United have enough quality in attack to trouble the best sides.
"As midfielders we know what our job is and how we affect games," he said.
"Maybe we are not noticed but we have quality players in advanced positions. Our job is to supply them."
Another possible midfield option for Ferguson is teenage signing Phil Jones, who has impressed since signing from Blackburn for 17 million in the summer.
Jones played a defensive midfield role for England in recent friendly victories over Spain and Sweden, and Fletcher is unsurprised by the 19-year-old's meteoric rise through the ranks.
"He has done fantastic and shown what a real quality player he is," said Fletcher.
"He has performed fantastically at full-back and watching the two England games he did really well in them as well.
"He has shown real quality and proved why the manager snapped him up."