FOR much of the season, it has seemed like attackers are on a list of prohibited substances at the Riverside. Last night, with Abel Xavier's positive A-sample still fresh in the memory, Steve McClaren found that forwards can be like the most potent of drugs. Used in the right way, they are certainly performance enhancing.

Jimmy-Floyd Hasselbaink marked only his fifth start of the season with Middlesbrough's tenth-minute winner as McClaren's side made a perfect start to the UEFA Cup's group stage.

With Mark Viduka also figuring prominently in a largely one-sided first half, the Boro boss was rewarded for the kind of bold selection the Riverside faithful have been urging him to make all season.

But, ultimately, it was the Teessiders' defensive strength that earned the 1-0 win that leaves Boro odds on to make the UEFA Cup knock-out phase for the second season in succession.

If Hasselbaink's goal was the stimulant for his side's success, the imperious Gareth Southgate was the all-important blocking agent. Time and time again, Grasshoppers' second-half attacking foundered because of his timely interventions.

Prior to kick-off, chairman Steve Gibson revealed he had held an "open and frank discussion" with McClaren in the wake of Saturday's soporific 1-1 draw with Portsmouth.

The topic of that debate was apparent from the Boro boss' team selection last night. McClaren might be a fan of playing with a single striker, but his chairman's argument in favour of a more attacking approach was clearly a persuasive one.

Viduka and Hasselbaink were re-united in attack, with a third striker, Szilard Nemeth, posted to the left wing in preference to the more defensively-minded Franck Queudrue.

Tellingly, it took just ten minutes for the policy to pay dividends. Displaying a vibrancy and drive that was absent from their play at the weekend, Middlesbrough's attackers tore into a Grasshoppers side of surprisingly limited ability.

Viduka was especially prominent in the early stages, twisting inside former Arsenal defender Igors Stepanovs within the opening five minutes and forcing goalkeeper Fabio Coltorti into a smart stop at his near post.

The Australia international has suffered from Aiyegbeni Yakubu's recent scoring spree but, at his best, he remains Boro's most incisive and intelligent attacker.

He was also involved in the visitors' opener when it arrived in the tenth minute. Doriva's give-and-go succeeded thanks to Viduka's perfectly-weighted lay-off and, when the Brazilian squared the ball across the box, an unmarked Hasselbaink was left with the easiest of side-foot finishes from no more than ten yards.

Nemeth should have added a second six minutes later but, after controlling Gaizka Mendieta's cross in the heart of the area, the Slovakian inexplicably chose to lay the ball off to the tightly-marked Viduka rather than pulling the trigger himself.

That was a mistake, but it was nothing compared to Mark Schwarzer's error that almost gifted Grasshoppers an undeserved equaliser midway through the first half.

Rogerio's long-range daisy-cutter looked innocuous enough but, not for the first time in his Boro career, Schwarzer made a complete mess of gathering it in. Eduardo tapped home the rebound, only for a questionable offside flag to spare the Australian's blushes.

The mood of the game had changed, though, and, buoyed by their unexpected opening, the Swiss hosts gradually gathered momentum.

Their attacking remained rudimentary, but left winger Antonio Dos Santos almost punished Boro for some slack marking three minutes before the break. The Brazilian swivelled onto Michel Renggli's lay-off, but could not keep his hooked half-volley under the crossbar.

It did not help that Middlesbrough's defenders had decided to camp on the edge of their own penalty area, a policy that had the inevitable result of inviting Grasshoppers' midfielders to join in their side's attacks.

Dos Santos did just that ten minutes after the break and, after he crossed from the left flank, his fellow Brazilian Eduardo headed over at the back post.

Boro's second-half approach was far more cautious than their first, with both Doriva and George Boateng rarely straying from the hole in front of their back four.

But, on a rare foray forward shortly before the hour mark, the former came close to doubling the visitors' advantage.

He seemed to be caught in two minds after bursting onto Mendieta's through ball and, while his cross-cum-shot whistled narrowly past the far post, it clearly infuriated the well-positioned Viduka.

McClaren would have been infuriated with the plentiful second-half possession enjoyed by the home side. With Dos Santos running Stuart Parnaby ragged down the left flank, Boro struggled to stem the flow of opposition attacks.

But, with Southgate and Chris Riggott throwing their bodies in front of a succession of speculative shots, Schwarzer remained a largely unaffected observer despite Grasshoppers' territorial dominance.

Southgate made a telling intervention to deflect Eduardo's goalbound header wide of the target with 15 minutes left and, when Boro's goalkeeper was eventually called upon, three minutes later, he was up to the task.

Rogerio's stooping header was creeping inside the right-hand upright until Schwarzer, who withstood a hail of coins and cigarette lighters, flung himself to his left to turn it round the post.