Alex Ferguson has proved over the last decade that he is a master of assessing the dangers of burning out his Manchester United youngsters. His latest need for that extensive knowledge is in harnessing the exciting talent he possesses in Cristiano Ronaldo and Wayne Rooney.
Ryan Giggs was Ferguson's prototype, the wily manager carefully blooding a precocious Welshman before launching a collection of his "fledglings" - the Neville brothers, David Beckham, Paul Scholes, Nicky Butt et al - to title-winning glory.
Rooney, the costliest teenager British football has known, is going to be high maintenance as Ferguson seeks to make maximum use of his erratic brilliance. A failure to take the clearest of chances against Aston Villa on Saturday was the most fitting illustration of a poor display by the England striker.
In contrast, Ronaldo, as Ferguson readily agreed, turned in his best performance of the season to tip the balance in an entertaining tussle with David O'Leary's visitors, scoring the opening goal and setting up the clinching third in a deserved, if at times laboured, victory.
A holiday back home in Portugal during the Christmas schedule clearly enabled Ronaldo to recharge his batteries at a time when opposing defenders were beginning to get the measure of his step-over party piece. He has returned revitalised, scoring the opener in the FA Cup win at Exeter on a night Ferguson suggested could have brought him five goals, and then turning on this exhilarating demonstration of his prowess on the wing.
United will go into the Middlesbrough match without Roy Keane, their influential captain, who incurred his fifth caution of the season for a late challenge on Villa midfielder Lee Hendrie.
Mark Halsey was astute in his judgment then, but the Lancashire official was less severe in dealing with a clash between Nolberto Solano and Mikael Silvestre which bore a remarkable similarity to the recent incident which earned Rooney a suspension for a brush with Bolton's Tal Ben Haim. Fortunately for Solano, Silvestre did not over-react to having a hand thrust into his face.