And grateful. Aston Villa discarded McGrath at the start of this season, a touch prematurely perhaps, but Derby's 3-1 FA Cup victory over his old club did not give rise to smug satisfation. "I don't think about what I gave to Villa," he said, "but what they gave to me. A new lease of life, a new career. I'll always be grateful for that, and today the Villa supporters were great, giving me a cheer before the game and at the end. That was nice."
Nothing about McGrath's turnout conveyed the idea of stardom. Scruffy, you might say, in contrast to the unfailing tidiness of his football. Following majestic performances for the Republic of Ireland in the 1994 World Cup finals, people wondered how much longer his battered legs would hold up. "Paul is remarkable," Derby's manager, Jim Smith, said. "If we could get him new knees, I think he would go on for ever."
Long enough, Smith hopes, to help consolidate Derby's status as they prepare to abandon the ancient Baseball Ground for a new stadium that is rapidly taking shape on the outskirts of the city.
In Derby's case, the FA Cup provided relief from the grind of survival, and it showed in the confident urgency of an approach that Villa were never able to counter. And this despite the absence of first-choice defenders, further complicated when Jacob Laursen was injured in the pre-match warm- up. Losing Gary Rowett after 16 minutes was another blow but it seemed that nothing could undermine Derby's spirit. "They were better than us," Villa's manager, Brian Little, said. "We had a couple of half-chances early on that might have changed things and if we could have got within one goal of them it might have been different, but to be honest, once Derby went in front I couldn't see us winning."
Reverting to a conventional back four when Rowett went off, Derby might have been most vulnerable in a period of reorganisation, but before Villa could take advantage they fell behind when Robin van der Laan was first to Paul Simpson's neat lob.
The key figures in all this were McGrath, who brought his vast experience to bear on proceedings, sometimes performing decisive tricks of improvisation, and Aljosa Asanovic. The way Asanovic moved the ball around and his astute appreciation of space was better than anything on offer from Villa's midfield.
No sooner had Van der Laan taken an opportunity to re-establish himself than Asanovic conjured a goal for Paul Sturridge, whose pace and determination made him a constant threat.
The loss of Andy Townsend at half-time with a shoulder injury added to Villa's problems, and although they raised the tempo, releasing Steve Staunton into attack, they were out of it when Ron Willems completed a move that involved Asanovic, Sturridge and Paul Trollope.
These are not the best of times for Sasa Curcic -"the worst move I've ever made" he has said controversially about a pounds 4m transfer from Bolton - and not much in the way of congratulation was evident when he fired past Russell Hoult from 25 yards.
From being one of the Premier League's fancied teams, Villa appear to have lost their way to the point where Little admits that the rest of the season will be spent in re-assessment. Passion does not figure in his public utterances. "We didn't deserve anything," he said. "I've just spent 15 minutes telling the players that we must concentrate on finishing as high in the League as possible."
It is Jim Smith's priority too but there are a lot fewer clubs beneath Derby. As for McGrath, he was more eager to dwell on what Christian Dailly had contributed to Derby's victory as a makeshift central defender than his own almost immaculate perforance. But then that's always been one of the big Irishman's charms. Underselling himself.
Goals: Van der Laan (36) 1-0; Sturridge (40) 2-0; Willems (69) 3-0; Curcic (76) 3-1.
Derby County (3-5-2): Hoult; Dailly, McGrath, Rowett (Simpson, 19); Carsley, Van der Laan, Asanovic, Trollope, Powell; Sturridge, Willems. Substitutes not used: Gabbiadini, Rahmberg.
Aston Villa (3-5-2): Bosnich; Ehiogu, Staunton, Southgate; Scimeca, Townsend (Nelson, h-t), Hendrie, Curcic, Wright; Milosevic, Yorke. Substitutes not used: Tiler, Oakes (gk).
Referee: J Winter (Cleveland).
Man of the match: Asanovic.