MIDDLESBROUGH are keeping as close an eye on the weather as on the fitness of key defenders Gareth Southgate and Ugo Ehiogu ahead of tonight's Carling Cup semi-final decider against Arsenal.

With skipper Southgate and Ehiogu doubtful because of hamstring and groin injuries, the arctic conditions could be welcomed down by the Riverside.

But Boro will be anxious not to be drawn into a repeat of the row which flared last season following the postponement of the derby visit of Newcastle.

Magpies boss Sir Bobby Robson accused Boro, who were hit by injuries at the time, of collusion in calling the game off - 28 hours before it was due to be played - after heavy snow.

Although the pitch was playable, the terraces and approaches to the stadium were deemed unsafe by police and officials. Robson's anger intensified when a thaw the next day meant there wasn't a flake of snow around the Riverside.

An inflatable pitch cover is again being employed by Boro, and manager Steve McClaren stressed he was "very confident'' tonight's match would go ahead.

But he is already without the vastly-experienced Colin Cooper with a hamstring problem and admitted he is "sweating'' on the availability of his much-vaunted Southgate-Ehiogu central defensive pairing.

Both missed Saturday's FA Cup fourth-round defeat by Arsenal at Highbury and are rated no more than 50-50 to return for the fourth and last instalment of the sides' 18-day series.

In between 4-1 defeats at Arsenal, the first of which was in the Premiership, McClaren's side achieved their first win over Arsene Wenger's men at the eighth attempt when Juninho grabbed the only goal of the first leg of this semi-final in North London.

Now, eight days later, Boro are on the threshold of reaching their third League Cup final in seven years after bitter defeats by Leicester, in a replay, and Chelsea in 1997 and '98 during the reign of Bryan Robson.

Like his predecessor, McClaren is fuelled by an overwhelming desire to bring Boro the first major trophy in their 128-year history and a place in Europe.

The prize for the winners tonight is a trip to Cardiff's Millennium Stadium at the end of next month and a date with Bolton or Aston Villa ???

Arsenal are again expected to field an under-strength side, as they did in the first leg, though skipper Patrick Vieira is likely to provide his prodigious influence in midfield and winger Robert Pires is said to have an outside chance of featuring.

Dennis Berkamp's fear of flying ruled him out, so the Gunners' attack will be formed by teenagers David Bentley and Quincy Owusu-Abeyie.

McClaren stressed: "It's one of the biggest games for this club for many years. The job is only half done and it's a great opportunity to finish it off.

"But it's going to be difficult. Whatever team Arsenal put out, it will be a very good one. We need our best players available and we're sweating on Southgate and Ehiogu. They've trained and we'll have to see if there is any reaction.

"We had chances to score a second at Highbury which we failed to take and 1-0 is a very slender lead.

"I don't think it was that bad a performance at Highbury on Saturday; I thought 4-1 was a bit flattering to Arsenal.

"We've had setbacks against them, but I think the first leg was significant in that we showed we could bounce back and we need to do the same this time.

"As I've said, this competition has been a bonus this season for our fans and hopefully we can make it an even bigger bonus.

"The only pressure I feel is what I put on myself to win silverware - that's what I came here to do and we're one step away.

"It's the most important game of our season so far, but we have experienced players who can deal with these occasions.''

Much could be expected of Chris Riggott at the heart of defence, and McClaren said: "Chris has been magnificent. I thought he was our best player on Saturday.''

With his defensive resources stretched to the limit, McClaren is relieved to have Stuart Parnaby at his disposal. The full back injured his back when he fell over an advertising hoarding at Highbury on Saturday, but he returned to training yesterday.

Brazilian midfielder Doriva, who missed the game through suspension, is available again.

If Ehiogu plays, it will be his 400th career game in League and Cup.

Chairman Steve Gibson this week admitted Boro are trying to push through a permanent deal for on-loan Leeds right-back Danny Mills before this weekend's transfer deadline, and that Manchester United midfielder Nicky Butt is wanted on Teesside.

However, McClaren said: "Nicky is a player I've always admired, but we've made enquiries and the latest I have is that he is staying at Man. United.

"We're trying to get Danny. I wanted him at the start of the season, I want him now and I want him at the end of the season. I'm very confident that, eventually, he will be a Middlesbrough player.''