Everton's hopes of securing Champions League football were dealt a huge blow as two first-half own goals gifted Southampton a 2-0 victory at St Mary's.
Already a point behind fourth-placed Arsenal, the Toffees knew a fourth successive away win was required in order to keep their charge for Champions League qualification alive.
However, first-half own goals from Antolin Alcaraz and Seamus Coleman cost Everton dear as Southampton secured a deserved 2-0 win that saw the club equal their best ever Premier League tally of 52 points.
The visitors were fighting an uphill battle after just 53 seconds at St Mary's as a rusty-looking Alcaraz directed past goalkeeper Tim Howard, with Ireland international defender Coleman following suit after 31 minutes to double Saints' advantage.
Everton attempted to claw their way back but few of their fans could argue with the result, which would have been worse was it not for wayward finishing and referee Michael Oliver waving away several penalty appeals.
Rickie Lambert – one of several English players impressing in front of England manager Roy Hodgson – also clipped the post with a 25-yard free-kick as Southampton ended a three-match winless streak and handed Arsenal the opportunity to move four points clear of Everton with victory over Newcastle.
The defeat brought Martinez's men crashing down after last weekend's 2-0 victory against Manchester United.
That result saw their former manager David Moyes lose his job at the Old Trafford helm but also came at a cost for the Toffees, who lost key men Kevin Mirallas and Sylvain Distin to injury.
Their replacements Gerard Deulofeu and Alcaraz are by no means slouches, but the latter's rustiness cost his side with less than a minute on the clock.
In just his fourth league start of the season, the Paraguay defender appeared flustered by the attention of Sam Gallagher and rather comically turned a Lambert cross past Howard.
Alcaraz's moment of madness was the worst possible start for Everton, yet they did not collapse and Coleman soon darted down the flank and crossed for Romelu Lukaku.
The shot that followed, though, was poor and it took until the 15th minute for Martinez's side to muster a first shot on target, and even then Artur Boruc easily dealt with Deulofeu's tame strike.
Gallagher's ignored appeal for handball against John Stones was all Saints had to show during the spell that followed their goal, although they were by now in control.
Jack Cork got away a shot as an injury to Steven Naismith temporarily reduced Everton to ten men, with the Scotland international returning just in time to see former Rangers team-mate Steven Davis miss a glorious chance after a fine Lambert cut back.
The Toffees were getting little joy in attack, with Nathaniel Clyne particularly impressive in keeping Deulofeu quiet.
Leighton Baines whipped in a threatening free-kick on the one occasion the Saints right-back lost the duel with the Barcelona loanee, although the cross evaded his team-mates and Saints capitalised.
Not only adept at the back, Clyne is a fine attacking option and bombed forward before fizzing over a wonderful cross that was just too high for Stones to head clear, leaving the unsighted Coleman to helplessly direct into his own goal.
Lovren powered a header at Howard soon after as Saints looked for a third, and after Lukaku directed over Boruc's goal, referee Oliver rejected vocal handball appeals against Stones after the Everton defender handled an Adam Lallana cross.
Naismith had handball appeals of his own waved away in first-half stoppage time and continued to prove a nuisance when played resumed, with Cork doing well to block wide his effort on goal.
The Saints midfielder had an attempt of his own at the other end and Lallana struck at Howard, who was relieved to see a 25-yard Lambert free-kick clip the post and go wide.
Substitute Leon Osman joined team-mate Gareth Barry in the book after being adjudged to have taken a tumble in the box under a challenge from Lovren, before fellow replacement Aiden McGeady's cross was headed straight at Boruc by Lukaku.
Referee Oliver was again the focus as Shaw and Lallana saw penalty appeals waved away after apparent handballs by Coleman and Stones, before a rather relieved Boruc saw a Baines cross dip just wide.
Everton were attacking in numbers in an attempt to reduce the deficit and had a spot-kick appeal of their own rejected after James McCarthy claimed he was impeded by Lovren, although their attacking mind-set was leaving gaps at the back.
Lallana showed wonderful skill to burst to the byline but Lambert was unable to convert late on, while Howard did well to deny substitute James Ward-Prowse.