First Division St Johnstone reached their second semi-final of the season with a well-deserved Tennent's Scottish Cup victory at Fir Park.

Saints scored in each half through Peter MacDonald and Jason Scotland as they secured their fourth win over SPL opposition this season.

They should have added to their tally but Ross McCormack's late goal set up a frantic finish.

However Motherwell came nowhere near deserving a replay with an inept display - and missed the attacking threat of injured winger Darren Smith, who was replaced by Steven McGarry.

Saints also made one change with midfielder Martin Hardie in for the suspended Derek McInnes.

The Perth outfit had beaten Rangers, Dundee United and Falkirk earlier this season and their confidence was evident.

Well midfielder Brian Kerr had a 25-yard drive comfortably held by Kevin Cuthbert but the hosts were pegged back for the next 10 minutes.

Willie McLaren came close with two shots from the edge of the box, the first deflected wide and the other fumbled away by Graeme Smith.

Smith was sharply off his line to block from Scotland after the striker wriggled his way to the touchline.

The Trinidad & Tobago international was racially abused by a small section of fans in the main stand before their fellow Motherwell supporters shouted them down.

Well briefly regained their composure and Cuthbert was forced to stop McGarry's header - but a high ball into the home box caused panic and Martyn Corrigan superbly blocked Hardie's close-range strike.

And it was no surprise when MacDonald flicked McLaren's pullback in off the bar with the outside of his boot in the 20th minute.

Well were struggling to keep the ball and the direct attacking of their opponents had them rattled.

Smith held on well to Paul Sheerin's volley and Scotland's header then dipped just over the bar, before the former Rangers keeper brilliantly pushed wide Hardie's header.

Well could not build any attacks and a frustrated Scott McDonald decided to take matters into his own hands, twice shooting wide from just outside the area.

The home support had given their side vociferous backing at the start but boos rang out as the half-time whistle blew. McCormack won a free-kick 25 yards out after a surging run seconds after the restart but his long-range shooting had been off target all night and the latest effort was no different.

Well were in dire need of a change and Trevor Molloy came on for McGarry before the hour mark.

The Irishman set up Corrigan but the full-back's weak effort was neither a shot nor a cross and summed up Motherwell's lack of conviction.

Saints attacked in numbers whenever they had the opportunity - and after Hardie's curling effort was parried away by Smith they doubled their advantage.

The SPL side's troubles increased in the 72nd minute when Scotland headed home from six yards after Goran Stanic had crossed from the byline.

Simon Mensing twice came close, Smith blocked Sheerin's volley and MacDonald blasted just wide as Saints chased a third goal.

Smith again saved from MacDonald after some poor defending, before Well gave themselves a lifeline in the 84th minute.

McCormack got the hosts off the mark, grabbing his first goal for the club when he side-footed home a McDonald cross.

Moments later Motherwell sub David Clarkson went down in the box and Mike McCurry clearly started to signal for a penalty before changing his mind.

McCormack's powerful drive bounced into Cuthbert's hands as Well threatened an unlikely replay, but Saints came closest to scoring another when Andrew Jackson's shot was cleared off the line.

Teams

Motherwell Graeme Smith, Corrigan, Craigan, Reynolds,Murphy (Clarkson 73), McGarry (Molloy 58), Kerr,Fitzpatrick (Keegan 82), Paterson, McCormack, McDonald.

Subs Not Used: Martin, Quinn.

Goals: McCormack 85.

St Johnstone Cuthbert, Lawrie, McManus, Mensing, James,Stanic, McLaren (Morais 83), Hardie, Sheerin,MacDonald (Milne 90), Scotland (Jackson 89).

Subs Not Used: Halliwell, Dyer.

Booked: Hardie.

Goals: MacDonald 21, Scotland 72.

Att: 5,788

Ref: M McCurry (Scotland).