The Scot turned 71 on Monday, his competitive spirit apparently undimmed in his 27th year at Old Trafford and with his team seven points ahead of Manchester City in the Premier League title race.
Whether Ferguson will get to celebrate a 13th championship in May - not to mention the third European Cup victory he covets so much - is likely to rest on United's defensive strength.
"I can't possibly answer it," he said after United came from behind three times to beat Newcastle 4-3 last week. "We've analysed it to every possible detail to try to get a constant thread that tells me how to address it.
"It's either don't attack at all, which is not going to be Manchester United, or let our supporters live through the agony of 4-3 wins. We've not had a 5-4 yet or a 6-5. I think that could be more exciting."
"It does matter, of course it matters," he said of the goals against column. "If we're scoring four goals at home there should be one against us or nothing. That's one way to help your goal difference. So that's always a concern.
"The concern about losing goals is that it's testing us to the very limit and making us play beyond the energy levels we need to."
'RUDE AWAKENING'
Vidic returned from three months out against Sunderland in December, and his continued presence beginning with the trip to Wigan Athletic on New Year's Day will be key to fulfilling United's ambitions in the next four-and-a-half-months.
"It is important we don't sit at the top of the table admiring our position," Ferguson said. "We would soon get a rude awakening. Congratulating ourselves on our Premier League lead doesn't mean a thing to me, it's winning the next game that counts."
