Rainworth fell victim to the slippiest banana skin of the season, gifting Parkgate their first league win in 18 attempts.
Ben Thornton’s 34th minute strike punished an unacceptable first half performance by the Wrens and was enough to seal the 1-0 victory for the Steelmen despite Rainworth’s better second half.
Watts went for broke midway through the second half, withdrawing two defenders in a bid for more fire power.
It was a high risk strategy which almost paid dividends, but left them vulnerable to the counter-attack, the Rotherham side always dangerous.
Rainworth’s disappointment was tempered to some extent by the fact that their hosts had recently brought in a new manager and several new players who began to gel for probably the first time.
There was no action of note from either side until the 13th minute when Wrens keeper Ben Townsend got enough of a touch onto Thornton’s teasing cross to divert it over the bar.
The travelling fans had to wait until the 21st minute for any worthwhile goal attempt, Ryan Herbert aiming wide.
Parkgate then attacked to devastating effect when Townsend managed to get a hand to Thornton’s shot, but couldn’t keep it out.
Rainworth did almost pull it back two minutes before the break, when Connor Griffin sent Matty Sykes on a run into the box from the left, but home keeper Josh Lill superbly blocked.
In the second half the Wrens had what looked a cast iron penalty claim denied by referee Andrew Dallison when Declan Brewin went down under a clumsy challenge in the box.
After Lill saved well from Brewin, the unlucky Sykes headed against the bar.
The next goal, if there was to be one, looked crucial, and manager Watts gambled by sacrificing defenders Joe Cheeseman and Adlington.
It became something of an onslaught on the Parkgate goal, yet still the home side stood up to it, aided, it must be said, by some blatant time wasting on occasion.
But the risk of such gung-ho tactics was obvious, and only an out of this world challenge in the box by Rob Ludlam on Adam Johnson prevented a second Parkgate goal, and in added time the Steelmens’ sub was denied again, this time by Townsend with a superb sweeper’s tackle outside his area.
Rainworth Miners Welfare: Towensend, Adlington (Maturin-Drew 81), Griffin, Buxton, Cheeseman (Langford 67), Ludlam, Brewin, Herbert, Topliss, Poole, Sykes. Sub not used: Watts.
Referee: Andrew Dallison.