Celtic's title bobbles towards Hearts and Rangers on Scottish football’s desert amid 35-year first

With seven games remaining, Celtic are now third, five points behind leaders Hearts and two behind second-placed Rangers. The defence of their championship is now out of their hands. Missteps are required from those above them.

This was a wretched lunchtime assignment for Celtic, who never looked comfortable on a deplorable playing surface. Flooded earlier in the year due to incessant rainfall, the Tannadice pitch now resembles something from the Gobi desert.

United coped with conditions better. After a forgettable first half, Will Ferry broke the deadlock on 51 minutes and never looked back. Emmanuel Agyei landed a second strike not long after.

This win arithmetically keeps United in the hunt for a top-six berth, although they would need to win their last two pre-split matches against Rangers and Livingston and hope Falkirk don't pick up any more points. It's unlikely. Of more importance is that this win moves them ten points clear of the relegation play-off place.

Jim Goodwin's men showed more fortitude here than seven days ago when they blew a two-goal lead across the road at Dens Park against Dundee in stoppage time. Celtic were unable to mount any sustained periods of pressure to force jitters.

Captain Callum McGregor returned to the team after a calf niggle and the lesser-spotted Kelechi Iheanacho was handed his first start since December's Premier Sports Cup final. Iheanacho showed some flashes of quality but looked ruefully short of fitness. Both men vacated the premises before an hour had passed.

Celtic never found their stride. Their passing deteriorated as the match wore on and once United moved in front, their play became error-strewn and panicked. A sizeable away support chuntered away at the nick of their team in between the usual chants for the board to be sacked. There was an air of resignation at full time. To win the league, Celtic probably have to win all of their remaining matches now. That's a humungous ask for this team.

Chances were few and far between early on. The first meaningful opportunity came for Celtic on 13 minutes when a corner fell to Kieran Tierney in the penalty box, but he lashed at the ball and it flew over the bar.

United's first big moment arrived on 17 minutes. Ferry unleashed a fierce effort that was destined for the far top corner of Viljami Sinisalo's net, but the Finnish keeper showed excellent reflexes and tipped it away.

Celtic defender Liam Scales was correctly booked on 34 minutes for clumsily fouling Neil Farrugia in a promising position. Amar Fatah's free-kick was woefully poor and struck the wall.

Celtic's best chance of the first half came three minutes before the interval. Reo Hatate fizzed an accurate pass into Iheanacho's feet and the Nigerian's left-footed effort was beaten away by United keeper Ashley Maynard-Brewer.

United broke the deadlock six minutes after the break when Ferry met a low Luca Stephenson and while he hit the ball into the ground, it had enough purchase to beat Sinisalo via a slight touch off Colby Donovan.

Celtic nearly got the slice of fortune they required to level on 63 minutes when Maynard-Brewer fumbled a Hatate long-range strike on to his own post. Fortunately for keeper, the ball landed the right side of the line for him.

It was a big moment. Three minutes later, United doubled the advantage. Watters' effort was blocked in the penalty box but the ball fell kindly for Agyei and his strike skiffed off Scales and beyond Sinisalo.

A vexed Martin O'Neill went to his bench in a desperate attempt to shake things up. Junior Adamu came on up front to join Daizen Maeda in attack. The latter had a half-chance from close range on 82 minutes but prodded the ball wide. The hosts had their chances too and looked just as likely to add to their lead. In total, they peppered 18 attempts at Sinisalo's goal.

United were now in a time zone where they have too often conceded goals this season but they held firm. Celtic's creativity levels had evaporated in the Tayside sunshine. Having floored Wilfried Nancy's Celtic side in December, United did the home double over them for the first time since 1991.

This was Celtic's eighth defeat of the Premiership campaign. No team has won the league in the three-point era with that number of losses. And three of them have come in Dundee, a city where Celtic have discovered their limitations.