The Tannadice side sat second in the Scottish Premiership at the start of the festive week but suffered a 4-1 drubbing to St Mirren on Boxing Day, lost 3-0 to St Johnstone last Sunday before starting 2014 with another defeat after Pawlett grabbed a last-gasp winner in the Dons' 2-1 win on Tayside.
But the Perth loss came after United boss Jackie McNamara made eight changes to his side - resting the likes of Stuart Armstrong, Ryan Gauld and Gary Mackay-Steven.
Seven of those players came back in for the meeting with the Reds but could not save United from a third defeat in a week as they slipped six points behind Aberdeen and eight behind second-placed Motherwell.
Now Pawlett claims McNamara got his team selection all wrong.
The 22-year-old said: "Dundee United rested a few players against St Johnstone and it was as though they treated this as the big game for them.
"When we saw that we thought they were giving us respect and think we're a decent team. Maybe they didn't show enough respect to St Johnstone.
"I think over the 90 minutes we looked the stronger, fitter team so maybe it was a mistake by them."
A sell-out 14,000-strong crowd turned out to see a hotly anticipated match between two of the most talked about teams in the country.
But lousy weather conditions and a sense of nerves shared by both sides rendered the first 45 minutes an ugly spectacle.
However, United got the first break five minutes into the second half when Mark Wilson swung in a menacing corner which goalkeeper Jamie Langfield failed to read and John Souttar headed home.
Aberdeen levelled 15 minutes later though as referee Willie Collum ruled United left-back Andrew Robertson had used an arm in his own box when Barry Robson's through-ball skipped up off the turf and hit his armpit.
Robson blasted home the penalty and insult was added to injury for United when Pawlett stooped low to head in a 90th-minute winner after Radoslaw Cierzniak allowed Robson's free-kick to spill from his grasp.
McNamara said: "I spoke to Andrew and he thinks the ball hit him on the chest but the referee made the decision quickly. Sometimes they go for you and other times they don't.
"We're disappointed because it was a frustrating way to finish the match. There wasn't much quality in the game, it was a lot of free-kicks and stop start all the time.
"We've now lost three in a row but I wouldn't say it was a concern, the previous two games were different altogether because we were down to 10 men against St Mirren and St Johnstone."