When does a rookie coach cease to be on probation? With the first grey hairs around the temples? On his 40th birthday? Or when he stops being viewed as somebody else's disciple?
Two men still well short of 40 take charge of ambitious, fabled clubs in the Europa League on Thursday night.
Andre Villas-Boas, in charge of the London club, has been reminded long and loud lately that he has just passed the anniversary of the one major failure in his precociously decorated career.
Andrea Stramaccioni is shortly to mark a first year as a senior first-team coach, having been surprisingly promoted from Inter's youth team at the end of March 2012.
He was 36 when the summons came, initially to guide Inter through to the end of last season, the club's 17th different head coach in as many years.
Villas-Boas was only 34 when he was dismissed by Chelsea, another fall-guy in their impatient recent history of managerial shuffling.
By then Villas-Boas had already won a Portuguese League and the Europa League with Porto, with some of the upstart momentum Jose Mourinho, then age 40, showed at the same club a few years earlier.
Mourinho's rise helped make the young coach fashionable, caused presidents and chairmen to think twice about whether or a distinguished playing career was a necessary aspect of a manager's background.
Mourinho lacks that. So does Villas-Boas. As a former assistant to Mourinho at Porto, Chelsea and Inter, and a compatriot, he cannot escape comparison with his former boss, although his work at Spurs has seen him more roundly appreciated as his own man.
At Chelsea, being "Special Two", or "Mini-Mou", in the eyes of employers and senior players left him vulnerable to being considered a wet-behind-the-ears imitation, second best.
Stramaccioni, whose own playing days were stillborn thanks to injury, never worked with Mourinho at Inter.
Then again, nor did Antonio Cassano, although that did not stop the boisterous Italy striker angrily deriding his head coach after a practice session last week with unflattering comparisons, essentially telling Stramaccioni he had none of Mourinho's gifts.
The pair had a heated exchange, had to be physically separated. Cassano was then dropped, although he has returned to the match day squad for this evening.
"What happened was a normal tension of all dressing-rooms," said Stramaccioni of the clash.
But for a rookie coach, a routine row with a professional nursing a bruised ego carries extra connotations. Players often think they know better than their coach; when the coach is younger than the captain – Javier Zanetti, who wears the Inter armband, is two years older than Stramaccioni – authority must be negotiated before it is assumed.
Villas-Boas has learnt that. "He is young but very good at coming across as having a lot of experience," said Claudio Zelito Aguair, who was one of the senior players – and three years older than Villas-Boas – at Academica de Coimbra when the Portuguese took his first senior club coaching post there in 2009.
"And he was good at man management, knew when to be close to players and when to stand apart. He still has a lot of friends from Academica. I always thought he would be successful in England."
Certainly, the young but worldly Villas-Boas has given Spurs a zest to examine the tactical nous of his opposite number.
Steaua Bucharest v Chelsea: Tatarusanu ready to take on ‘Europe’s Queen’
On Thursday, Steaua host Chelsea in the Europa League last-16 first leg in Bucharest after the Blues narrowly negotiated their last-32 clash with Sparta Prague and the Romanians claimed a penalty shoot-out victory over Ajax.
The goalkeeper Ciprian Tatarusanu, the penalty shoot-out hero, said on www.uefa.com: “Chelsea are a better team [than Ajax] – they are the Uefa Champions League holders so they are obviously the stronger team.
“Sure, it will be much harder than a game against a top Romanian side – we are talking about ‘Europe’s queen’ – and I have no doubt I will have much more work to do than against a ‘normal’ European team.
“As we proved in the two games against Ajax, we can be a match for anyone, no matter who they are. Before every game – regardless of the competition – I don’t feel any pressure on me. All I focus on are positive thoughts, which help me take a serious and professional approach to each match, and be focused for every second.”
Like Chelsea, Steaua have one European Cup to their name, having won the continent’s most prestigious tournament in 1986.
This season is the first time they have reached the last 16 in Europe since 2005/06.
Laurentiu Reghencampf’s Steaua side are eight points clear at the top of the Romanian league and their only defeat in their last seven was the first leg with Ajax.
Tatarusanu believes the sum of Steaua’s parts can perform better than Chelsea’s undoubtedly talented individuals.
“Chelsea have more skilful individuals but we are a very solid group,” the 27-year-old said.
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