Mark Durnan (centre) scored United's winner
Mark Durnan's first-half goal took Dundee Utd into the Scottish Challenge Cup semi-finals with a second win in a week over Dunfermline Athletic.
The result did not reflect the visitors' overwhelming superiority.
And, for the second time in two games, the Pars had a player sent off, Lewis Martin being the man shown red for a professional foul on Blair Spittal.
Durnan's deflected shot secured the win, with the Pars claiming unsuccessfully for a late penalty.
United showed where their priorities lie by making eight changes in their line-up from the side that defeated their hosts in the Scottish Championship on Tuesday night.
But it did not stop their momentum.
Durnan scored his third goal in four games with only eight minutes gone, aided by a deflection that helped the ball squeeze in at the goalkeeper's right-hand post.
The East End Park home support in a crowd of 2,576 had just one thrill when Moffat came close from 20 yards.
However, that apart, they did not bother United goalkeeper Luis Zwick.
They went down to 10 men when defender Martin was correctly given a straight red card for pulling back Spittal to deny a clear goalscoring opportunity.
Dunfermline had one late claim for a penalty deep into five minutes of time added on.
Donaldson appeared to drag Farid El Alagui down right on the 18-yard line, but referee Willie Collum waved play on.
It was a poor match, but United were worthy winners.
Reaction
Dunfermline Athletic manager Allan Johnston: "I don't know if it was a penalty or whether it was in the box or not, but it was a clear free-kick anyway.
"Surely the referee's got to see that. The whole stadium seen it.
"I don't think there was a lot in the game at all. It was a bit scrappy at times.
"The boys did great when they went down to 10 men and I don't think it was a sending off either.
"He still had 40 yards to run and Lee Ashcroft was coming round to cover. Do you class that as a clear goalscoring opportunity?
"Our results haven't been good enough, but I think we've got players capable of turning it round."
Dundee United manager Ray McKinnon: "It has been a good week - three wins out of three.
"Eight changes today, with Dunfermline along the same lines as Tuesday and the same result as Tuesday, I am over the moon.
"We want to win the competition, but we want to utilise the squad properly and it was a good opportunity for some players coming back from injury to get fitness.
"A couple of kids got their debuts and, overall, it just shows me the squad's strong.
"We weren't slick by any stretch of the imagination, we passed up a few chances, but overall I've got to be pleased with that."
