England 277 and 19 for 0 (Burns 10*, Jennings 8*) lead West Indies 154 (Campbell 41, Wood 5-41, Moeen 4-36) by 142 runs
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A maiden five-wicket haul for Mark Wood has put England in command for the first time this series, with a 142-run overnight lead against West Indies in the third Test.
He had had to wait for his chance, but when it came, Wood lunged at it like a caged animal released.
A late call-up to the England squad after Olly Stone returned home with a back injury before the first Test, Wood remained on the sidelines until he was named to play his 13th Test, and first since May. It may have been a dead rubber, but it looked anything but, on an action-packed second day in St Lucia.
It was not until the 22nd over, with West Indies suddenly looking vulnerable - thanks to Moeen Ali - in their reply to England's first-innings 277, that Wood was finally let loose. What followed was a display of genuine pace, with Wood claiming 4 for 13 in the space of 4.2 overs, including two wickets in as many balls, to devastate West Indies' pursuit.
Wood, who has battled ankle problems for much of his career, finished with his best figures of 5 for 41 off 8.2 overs, while Moeen played a pivotal role - his 4 for 36 included the wickets of West Indies openers Kraigg Brathwaite and John Campbell, who had threatened to run rampant.
Moeen came into the attack in the 13th over after James Anderson and Stuart Broad had become increasingly frustrated by the opening pair, who had piled on their fourth half-century partnership of the series, in addition to their unbeaten stand of 17 in the series-clinching victory in the second Test.
Moeen had enjoyed some success against them, having dismissed both during the first Test in Barbados and Brathwaite again in the first innings in Antigua. And he repeated the dose at a critical juncture, with England in danger of losing control having lost their last six wickets for 45 in the morning session.
Campbell, in particular, looked threatening in St Lucia, surviving a couple of lbw appeals off Anderson and treating the England spearhead with disdain at times, not least with a lofted drive over the bowler's head and a nonchalant six flicked off his hip in the same over.
Anderson's reaction when he caught Brathwaite in the deep off Ali was low-key but then, on the next delivery, Moeen trapped Campbell lbw for 41 off 63 balls, his fourth score between 33 and 47 in this, his debut series.
Emboldened by the opportunity to charge in and rattle two new batsmen, Wood also responded two wickets in as many balls. His fourth delivery, to Shai Hope, was a 145kph bouncer that sent the batsman ducking to his knees out of harm's way, while his fifth - at 148kph - was sent by Hope straight to Rory Burns at gully. One ball later, the mode of dismissal was similar, with Roston Chase edging to Burns again.
Wood may have missed the hat-trick, but his next wicket was of enormous value to his team, removing the threat of another dangerous batsman, Shimron Hetmyer, caught cheaply by Joe Root at second grab in the slips with the final ball before tea. Wood and Root combined again after the break to dismiss Darren Bravo for 6, West Indies' most obdurate batsman of the Antigua Test unable to cope with the extra pace outside his off stump.
England had relied heavily on Ben Stokes to do a job with the ball in Antigua and while he appeared to bat without any discomfort from the bruised heel that had him in some doubt for this Test, he was not called upon to bowl after looking sore as he went through some warm-up deliveries in the field.
Broad shut down the resistance of Shane Dowrich (38), trapping him lbw with they type of legcutter that had proved effective for him in the previous match. When Broad then took a spectacular one-handed catch while reeling backwards from mid-off to dismiss Alzarri Joseph and hand Moeen his fourth wicket, Root threw the ball back to Wood to account for West Indies' last man, Shannon Gabriel, bowled for 4.
Gabriel had displayed some breathtaking pace of his own in England's first innings, breaking the fifth-wicket partnership of Stokes and Jos Buttler. The pair added just one run to their overnight stand of 124 before Gabriel's 146kph gem clattered into Buttler's stumps.
Jonny Bairstow endured a torrid time a the crease, not least when he was struck on the grill of his helmet as he bent back to dodge a 150kph Gabriel delivery. He was unscathed, but the same could not be said when he was stuck three times in the groin during the course of his innings, which produced just two runs off 33 deliveries.
Bairstow was bowled, a victim of Kemar Roach, who claimed four wickets as England produced another notable collapse - but, for once in this series, it did not seem likely to impact their prospects, courtesy of Wood's performance.