Gregor Townsend rued failing to build on the momentous victory over England after Scotland's Guinness Six Nations title hopes were extinguished by Ireland.

The Scots' campaign began with so much promise following the joy of a first Calcutta Cup success at Twickenham since 1983.

But their faint aspirations of Championship glory were snuffed out by Sunday's agonising 27-24 loss to the Irish, which followed last month's single-point home defeat to Wales.

A brave second-half fightback at Murrayfield proved to be for nothing as Johnny Sexton's late penalty condemned the Scots to a sixth successive loss to their rivals.

Townsend's agony was compounded by losing Finn Russell and Scott Cummings to injuries which are expected to rule them out of next week's encounter with Italy, while Jonny Gray also picked up a problem.

"That's the frustrating thing – that we've not been able to build on that excellent performance against England and back that up with one, if not two, victories," said the head coach.

"Twickenham set the bar and for 32, 33 minutes against Wales the following week we played as well as Twickenham, in some aspects we played better.

"But since then we've not been consistent over the 80-minute period, against Wales and today.

"Every game is different, you've got a different opposition, a referee who has a different interpretation, so you've got to adapt.

"As much as I am so down about the loss today – and I know our players and our supporters are too – there is still a lot to be proud of this team.

"It's two games in a row now that they have come back and created an opportunity to at least draw the game with a few minutes remaining and this team has had to be adaptable."

Scotland had been inactive for more than a month following the postponement of their clash with France due to a coronavirus outbreak in the opposition camp and their rustiness showed in a wretched set-piece performance.

Andy Farrell's visitors were firmly in control thanks to tries from Robbie Henshaw and Tadhg Beirne and the potent boot of Sexton.

Scotland burst back into life as Huw Jones and Hamish Watson followed up Russell's first-half score to draw level and set up a grandstand finish.

A mistake by Ali Price proved costly, allowing Sexton to kick the decisive penalty four minutes from time and take his tally to 17 points for the afternoon.

Influential fly-half Russell and locks Cummings and Gray had been forced out of a bruising encounter before the late drama.

Speaking about the injury concerns, Townsend said: "It is quite early to tell but Finn was removed from play with a concussion, so it's unlikely he will feature in six days' time.

"And Scott Cummings, we fear he may have a fracture in his hand, so if that's the case he won't be involved next week. Jonny Gray had a shoulder issue, so we will wait and see how he is.

"That's three players – I imagine there will be a few more that turn up at training on Tuesday sore and we'll just have to see where we are then."

Scotland captain Stuart Hogg, who added two conversions following the withdrawal of Russell, admits the narrow loss is painful to accept.

"It's a frustrating outcome. For large periods of that game we showed what we are about. We really challenged them. We probably just lacked that clinical edge at times," said Hogg.

"The big thing we've talked about in the changing room is not being in a position to be chasing the game. We believe we are a lot better than that and unfortunately we've had to chase 24 points, which isn't ideal.

"We know we're a lot better than that – a lot better than we showed at times. This one really, really hurts. It's really, really frustrating but what's happened has happened, we can't change it."

Ireland's Championship ambitions were derailed after round two following defeats to Wayne Pivac's Grand Slam-chasing Wales and France.

After bouncing back by beating Italy a fortnight ago, a second successive win moves them second in the standings.

Head coach Farrell praised his players' rapid response to being pegged back in Edinburgh but concedes there are plenty of improvements to be made ahead of next weekend's finale against England.

"My over-riding feeling is one of pride really," said Farrell.

"They got the seven points to draw the game and it would take down a few teams mentally.

"But they stayed together, they refocused, they regrouped, great kick-off, good chase, good pressure and they stayed next-moment focused.

"We got the turnover and big-game players, that's what they do, they take responsibility and Johnny put over the points.

"I have been here plenty of times and struggled with most teams I've been here with, so really proud to get the win, really proud in the way we started the game and ended the game but obviously there are things to work on."