Black's side were beaten at home against Celtic in the Scottish Premiership on Saturday after a defensive mix-up gifted Anthony Stokes the opportunity to score the game's only goal in the first half.
The leaders had chances to increase their advantage, but could not convert and Black was left to rue Motherwell's errors, as the club consider him to replace former boss Stuart McCall, who resigned last month.
"We showed them maybe a little bit too much respect," Black told BBC Sport.
"They're a good side. I don't think there was much belief in us in the first half-hour.
"We keep giving away silly goals and goals that we think can be prevented. It was a self-inflicted mistake from our point of view, which gave Celtic the lead."
Inverness Caledonian Thistle came from behind to win 2-1 at Dundee and reclaim second spot.
The hosts took the lead through Greg Stewart before Billy McKay forced the ball over the line in a scramble to level before half-time.
The game appeared to be heading for a draw until Ryan Christie converted late on to ensure John Hughes' men climb above Dundee United and within three points of Celtic.
Aberdeen leapfrogged Hamilton Academical into fourth position with a comfortable 3-0 success, thanks to goals from Ash Taylor, Niall McGinn and an Adam Rooney penalty.
Kilmarnock ended a run of five straight defeats with a 1-1 draw at Partick Thistle after Tope Obadeyi gave the visitors an 11th-minute lead only for Danny Seaborne to cancel it out eight minutes later.
And St Mirren's wait for a first home league win of the season goes on after Michael O'Halloran's deflected shot secured victory for St Johnstone at St Mirren Park.
