MIDDLESBROUGH crashed to their heaviest defeat of the season as they were comprehensively out-played by Championship leaders Southampton.

The Teessiders lost 3-0 at St Mary's, and the gap could have been even wider such was the extent of the Saints' dominance.

Southampton's attacking was as good as anything Boro have encountered all season, with Guly Do Prado's first-half double effectively putting the game beyond doubt before David Connolly added a third goal late on.

But Middlesbrough hardly helped themselves with some sloppy defending, particularly in the first half when the hosts threatened to score with almost every attack Boro came into the game with the best defensive record in the Championship, but were unable to live with the attacking capabilities of a Southampton side who boast a 100 per cent home record this term.

The hosts attacked at will in the opening period, and Boro's two-goal half-time deficit could have been even wider such was the extent of their opponents' dominance.

The Saints served notice of their threat early on, with defender Jose Fonte seeing his shot deflected narrowly wide after Boro failed to clear a corner, and claimed the lead in the 15th minute.

Danny Butterfield delivered a deep cross from the right and Do Prado stole ahead of Tony McMahon at the back post to plant a powerful header into the top corner.

Do Prado was at it again on the half-hour mark, claiming his and his side's second goal of the afternoon.

The impressive Adam Lallana stood the ball up from the left, Rickie Lambert nodded back across the area and Do Prado stooped to head home from close range.

The Southampton striker should have had a hat-trick before the break, but his side-footed shot hit the post in the 36th minute to end a slick passing move that again involved Lallana and Lambert.

Boro were outplayed for large periods of the first half, but Scott McDonald came close to reducing the arrears on the stroke of half-time.

Latching on to Nicky Bailey's through ball, McDonald went round goalkeeper Kelvin Davis but could only direct his shot into the side-netting.

The visitors improved at the start of the second half, although their goal threat remained limited.

Southampton continued to press, and Jason Steele was forced into an excellent save to turn Jack Cork's long-range strike around the post.

Tony Mowbray responded by introducing Alex Nimely and Faris Haroun, but Boro were almost undone again in the 70th minute. Richard Chaplow dispossesed Joe Bennett, but after he crossed from the right, Steele saved from Jose Fonte with his legs.

The Saints deserved a third, and it came with nine minutes left. Lambert skipped around Matthew Bates close to the touchline, and former Sunderland striker Connolly hammered home his pull back from eight yards.

SOUTHAMPTON (4-4-2): Davis; Butterfield, Hooiveld, Fonte, Fox; Chaplow, Cork, Hammond (De Ridder 83), Lallana (Schneiderlin 74); Do Prado (Connolly 55), Lambert.

Subs (not used): Bialkoswki (gk), Martin.

MIDDLESBROUGH (4-4-2): Steele; McMahon (Zemmama 73), Bates, R Williams, Hoyte; Robson, Bailey, Arca (Haroun 63), Bennett; Emnes, McDonald (Nimely 63).

Subs: McManus, Ogbeche.