A COMFORTABLE opening hour ushered Glasgow Warriors to the head of the Guinness PRO12 – at least until this afternoon – but their joy was tempered by a sloppy final quarter and the red card shown to Langilangi Haupeakui, the USA international, for picking up two yellow cards on his debut.

Gregor Townsend, the head coach, was sympathetic with his player, though, feeling that the first yellow card decision – which was not played sent back to the television match official – was clearly wrong, while the second was harsh.

So if there is any question of a sanctions, he is sure they will fight it. "I will have to work out the process because it was two yellows, not a straight red," Townsend said. "We will argue very strongly about the first yellow card, we saw the arms were used [in the tackle]. We want our players to tackle low and use their arms and that is what he did.

"We have the lowest penalty count of any team in the PRO12 so discipline has not been an issue."

"Langi's first yellow card, it was a clear tackle, he goes low and put his arms round. I don't know why that was not referred to the TMO for such an important decision. The referee felt it was not a tackle using the arms but we say otherwise.

"The final one, I can understand why the referee thought that had not used his arms. It was a big impact and he was not able to get his arms round but it was a disappointing debut for Langi who was trying to get involved in attack and defence."

It all put a bit of a downer on an evening when Glasgow should have been celebrating their return to the top of the table, even if they can be overtaken when Leinster and the Ospreys are both in action later today.

After the disappointments of last week the question was: how badly had morale been affected? We did not have to wait long for an answer. Glasgow could, maybe even should, have had two tries inside the first three minutes – both by Stuart Hogg, the full back. First he misjudged his dive to the line after collecting his own kick ahead and then he was called back for a problem witht the quick throw in that had started the move that ended with him sprinting over.

The attacking position was not lost, however, and though it did take a little longer than it should have, the try did come with Jonny Gray, the captain, eventually finishing a series of forward drives.

Soon it was up to the backs to show they could match the brute force approach with a bit of rapier, Tommy Seymour, returning from a back injury, making the first inscision, with Mark Bennett taking the offload and wrongfooting the defence on a jinking 40-metre run to the line.

Treviso did hit back as a Finn Russell kick rebounded to Dean Budd, the flanker, whose pass inside seemed to have been knocked on before Alex Dunbar took out the supporting player and not only got himself sent to the sin bin but saw Treviso awarded a penalty try as well.

Not that it did much damage to the Glasgow cause, with Rory Hughes, the wing, on a scissors move with Henry Pyrgos straight from a scrum to go under the posts for his first home try for the Warriors.

Within a couple pf minutes of serving his sideline sentence Dunbar for his revenge for any miscarriage of justice by completing the first half scoring, picking up a loose ball and powered through a weak double tackle to reach the line for the scoring bonus point.

The fifth try came soon after the break with as Glasgow drove their scrum and spun the front-foot ball out to the backs where Hogg came into the line as the extra man and put Hughes over for his seocnd of the night.

As often happens, that was the cue for wholesale changes that cost all the Glasgow fluidity. The bnig thing for the home crowd was that they did get their first look at first Brian Alainu’uese, the giant NEw Zelander, and later a brief look at Langilangi Haupeakui,the American, before he was sent to the sin bin when he was judged not to have used his arms in a tackle round the side of a maul.

The mistakes multiplied and the tries dried up a result, with Treviso using their advantage to earn a penalty on the Scots line and maul it in for a try, Davide Giazzon, the replacement hooker, getting the score.

The final period was pretty much a stalemate with mistakes on both sides until Haupeakui was judged guilty of the same offence for second time and this time the second yellow card turned to red as he left the field for the final minutes.

Glasgow Warriors: Tries: Gray (6), Bennett (12), Hughes (28), Dunbar (38). Cons: Russell 3 Benetton Treviso: Tries: Pen try (24), Giazzon (63). Cons: McKinley, Allan.

Scoring sequence (Glasgow Warriors first): 7-0, 12-0, 12-7, 19-7, 26-7 (half time), 31-7, 31-14,

Glasgow Warriors: S Hogg (L Jones, 73); T Seymour, M Bennett, A Dunbar, R Hughes; F Russell (P Horne, 59-77), H Pyrgos (C) (A Price, 59); A Allan (D Sears-Duru, 70), P MacArthur (C Flynn, 51), S Puafisi (D Rae, 51), T Swinson (B Alainu’uese, 51), J Gray (C), J Strauss, S Favaro (L Haupeakui, 55, sin bin: 62-72, red card: 78), R Wilson.

Benetton Treviso: J Hayward; D Odiete, T Iannone, A Sgarbi, A Pratichetti (A Esposito, 55); I McKinley (T Allan, 51), T Tebaldi (E Gori, 59); N Quaglio (F Zani, 59), L Bigi (D Giazzon, 51), S Ferrari (rep:T Pasquali, 59), F Gerosa, M Fuser, D Budd, A Zanni (C) (M Barbini, 41), A Steyn (F Minto, 69).

Referee: D Wilkinson (Ireland)

Attendance: 7,251