Jimmy Floyd Hasselbaink ensured a winning start to Middlesbrough's UEFA Cup Group D campaign with his first goal of the season earning his side a 1-0 win despite a resilient fightback by Grasshoppers.
The Dutchman fired the Teessiders ahead with just 10 minutes gone, and had Szilard Nemeth taken advantage of two golden opportunities to make it 2-0 before the break, the result would not have been in any doubt by the time the half-time whistle sounded.
However, he did not and the home side - who had an equaliser harshly ruled out for offside - dominated the second 45 minutes to such an extent they will feel unfortunate to have lost.
Where Gaizka Mendieta and Hasselbaink had been the leading lights in the first half, Gareth Southgate and the excellent Chris Riggott came to the fore after it to ensure a three-point start, just as Boro managed at the same stage of the competition against Egaleo in Greece last season, at the end of a week which started with news of Abel Xavier's failed drugs test.
There were only around 700 travelling fans among a crowd of 8,500 at the 17,600-capacity Hardturm Stadium, but they left delighted with the result and elements of the performance, although concerned that the inconsistency which has dogged their side so far this season could be so evident within the space of a single game.
Boro chairman Steve Gibson was an early arrival at the stadium after agreeing to reply to fans' calls on a radio phone-in before kick-off, and he revealed he was furious at the performance against Portsmouth and made his feelings known in a frank discussion after the final whistle.
McClaren, who played Aiyegbeni Yakubu as a lone striker at the weekend, responded by pairing Hasselbaink and Mark Viduka in attack and asking Mendieta and Nemeth to provide the width in midfield, and the result was largely satisfactory at first.
The Teessiders dominated the opening 45 minutes and should really have been out of sight after pulling a defence which included former Arsenal stopper Igors Stepanovs all over the place and creating chances almost at will.
Goalkeeper Fabio Coltorti had already saved a Mendieta free-kick and blocked a Viduka shot on the turn with his legs when he was forced to pick the ball out of his own net after Nemeth and Doriva had combined to present Hasselbaink with the simplest of chances to open his season's account.
Nemeth should have made it 2-0 within six minutes, but inexplicably chose to try to pass to Hasselbaink instead of shooting, and he dragged another effort wide on 25 minutes with the goal gaping once again.
Boro's dominance was a reflection of a largely woeful display by the Swiss side, who played some nice football in the middle of the park, but simply could not bring their strikers into play with any regularity until Ricardo Cabanas and Antonio Dos Santos rallied late in the first half.
That said, however, they were desperately unfortunate not to be level on 21 minutes when keeper Mark Schwarzer had cause to be grateful to the referee's assistant.
The Australian spilled Rogerio's long-range shot far enough for Eduardo to reach the rebound first and slam it past him into the empty net only for an offside flag to rescue him, although television replays suggested the decision had been harsh on the striker.
Dos Santos fired over the bar from close range three minutes before the break with Boro losing their concentration momentarily, but McClaren's men left the pitch at half-time knowing they should already have had the points wrapped up.
Dos Santos drifted a free-kick harmlessly out of play early in the second half before Michel Renggli hammered another high over Schwarzer's crossbar.
Schwarzer was called upon in the 50th minute to keep out Cabanas' well-struck drive, and as the pressure started to mount, Eduardo headed wide from Dos Santos' excellent far post cross.
Doriva should have killed the game off on 56 minutes after Mendieta had torn Grasshoppers apart, but the Brazilian drilled his low effort wide of the far post with Viduka completely unmarked and none too pleased in the middle.
Rogerio kept Schwarzer on his toes with an audacious backheeled effort from Kim Jaggy's cross on the hour, and the pressure was mounting.
Riggott unwittingly blocked an Eduardo piledriver on 70 minutes with Boro retreating further and further into their own half, and Schwarzer had to claim a swerving Cabanas free-kick three minutes later.
Riggott was relieved to see a Rogerio flick drop just wide of the post after it had flicked off him with 15 minutes remaining.
Schwarzer pulled off a fine save to keep out Rogerio's 78th-minute header - but Grasshoppers could not fashion a breakthrough.