Both players have improved since making career changes; Townsend from Northampton to Brive, Humphreys from London Irish to Dungannon. On 10 April Townsend has a chance to elevate his country to a share of the championship; for Humphreys, who tasted nectar when Ulster won the European Cup, the Five Nations stage had a trap door.
"Gregor has his pace back, he's maturing and shaping games very nicely," John Rutherford, the former Scotland outside-half and now assistant coach, said. "That was one of the best games he's ever played."
Townsend should be in his element when Scotland play France in Paris in three weeks' time. If he scores a try he will become only the fifth player in the 89-year history of the championship to cross the line against every other country in the same season.
In previous seasons Towns-end's star has not been quite as bright, probably because Northampton and Scotland, weren't sure whether to play him at outside-half or centre. The try he scored against Ireland here was a classic centre's move, receiving, instead of giving, a pass from John Leslie.
Jim Telfer's promotion of Leslie has been a great success, not only for Scotland but for Townsend. The two have developed a canny relationship and their innate skills mean that they invariably do the right things at the right time. Having a player of Leslie's ability outside him has clearly boosted Townsend's confidence.
By contrast Humphreys does not have a Leslie at his shoulder to exploit the opportunities created. With his first touch, Humphreys expertly released the dynamic Dion O'Cuinneagain in an attack that resulted in a penalty try and a 7-0 lead in the second minute.
The fact that Ireland failed to cross the Scottish line again on Saturday was not only down to the tenacity of the home defence but the sterility of those around Humphreys and the futility of the game plan. Their inability to finish off what Humphreys starts has been obvious from match one when Ireland failed to score a try against France in Dublin despite a glut of possession.
Keith Wood's try against Wales at Wembley seems to have persuaded coach Warren Gatland that the hooker is Ireland's most potent weapon. Wood spends as much time loitering in the threequarter line as he does in the pack but there is no longer an element of surprise in seeing him used as a battering ram. Had he been employed as a decoy, Ireland might have prospered.
And that was not the only area of play in which they had Wood sussed. England's assistant coach, John Mitchell, had spotted that it was easier to pinch ball off Wood's throw-in. A little twitch of Wood's hand signals when the ball is being released and Scotland, too, exploited this with Scott Murray winning three Irish line-outs.
Throughout the championship, Gatland has been reluctant to trust his backs. Scot- land, on the other hand, have been reinvented. Their four tries against Ireland took their total in three games to 11. Ireland have three tries from four matches. Perhaps the difference was encapsulated midway through the second half when Wood made his umpteenth charge in the shadow of the Scottish post, the ball was lost and Townsend's break, supported by Glenn Metcalfe, Cameron Murray and Leslie ended in a wonderful try by Stuart Grimes.
"I'm absolutely delighted," Gary Armstrong, the Scotland captain, said. "There's now real belief in this team. We have been working hard on counter attacking and it paid off."
Even without their Lions' prop Tom Smith, who broke a leg just before half-time, Scotland will fancy their chances at the Stade de France.
SCOTLAND: G Metcalfe (Glasgow Hawks); C Murray (Hawick), A Tait (Kelso), J Leslie (Sanix), K Logan (Wasps); G Townsend (Brive), G Armstrong (Newcastle, capt); T Smith (Dundee High School FP), G Bulloch (West of Scotland), P Burnell (London Scottish), S Murray (Bedford), S Grimes (Watsonians), P Walton (Newcastle), E Peters (Bath), M Leslie (Edinburgh Reivers). Replacements: D Hilton (Bath) for Smith 40; B Pountney (Northampton) for Walton 67; S Longstaff (Dundee HSFP) for C Murray 75; S Brotherstone (Melrose) for Bulloch 77; I Fairley (Kelso) for Armstrong 79.
IRELAND: C O'Shea (London Irish); J Bishop (London Irish), K Maggs (Bath), J Bell (Dungannon), G Dempsey (Terenure College); D Humphreys (Dungannon), C McGuinness (St Mary's College); P Clohessy (Young Munster), K Wood (Harlequins), P Wallace (Saracens), P Johns (Saracens, capt), J Davidson (Castres), D O'Cuinneagain (Sale), E Miller (Terenure College), A Ward (Ballynahinch). Replacements: V Costello (St Mary's College) for Miller 16; R Henderson (Wasps) for Bell 63, T Brennan (St Mary's College) for Ward 64; C Scally (University College Dublin) for McGuinness 75.
Referee: D Bevan (Wales).Reuse content