It is hard to believe after this destruction of West Ham that only a few weeks ago Sunderland were being tipped for relegation and David Vaughan was unwanted by Martin O'Neill.
Performances were bad enough to put O'Neill under pressure. Sunderland could not score goals unless Steven Fletcher did. They looked weak in defence, lightweight in midfield and lacked all creative spark.
They rebuilt over Christmas, beating Manchester City on Boxing Day. The recovery was down to hard work and determination but, for the first time on Saturday, they played like a team that could be destined for better things.
From back to front, they were superb. Titus Bramble and John O'Shea were immense at the back, Adam Johnson looked like an -England player again, Stephane -Sessegnon looked good enough to grace any stage and James McClean was a bustling bundle of energy on the wing.
None of them, though, could beat Vaughan to the man-of-the-match award. The Wales international was the midfield metronome that made Sunderland tick, spreading play, but also hustling and harassing to win possession back.
Punished for an awful performance against Middlesbrough in October, Vaughan looked unlikely to get another look-in until injuries mounted. "He started against Bolton and he was our best player," said O'Neill, who retained Vaughan ahead of new signing Alfred N'Diaye. "He was trying to get it down and manoeuvre it. He was excellent. I'm not sure anyone played better than him."
West Ham fell behind to an excellent strike from Sebastian Larsson, but Sam Allardyce described their defending for the other two goals, from Johnson and McClean, as "pathetic". The manager also admitted his side looked "woefully short" of what they need to avoid relegation. Their misery was compounded by James Collins tearing a hamstring.
Allardyce will rekindle his pursuit of West Brom defender Jonas Olsson this week and discourage Newcastle's interest in his centre-back James Tomkins.