An improbable career-best knock of 92 from nightwatchman Jack Leach underpinned England's fightback against Ireland at Lord's but the visitors remained in the hunt for one of Test cricket's biggest upsets.

England ended day two of the inaugural Specsavers Test between the neighbouring nations on 303 for nine – a lead of 181 – after lightning and rain brought an early end to proceedings.

With the game so finely poised all three results remained on the table but England may already have been staring down the barrel of an remarkable defeat had it not been for a steadfast knock from Leach.

The left-hander vaulted from number 11 to an emergency role at the head of the innings late on day one and went on to share a stand of 145 with debutant Jason Roy, who scored an attacking 72.

By the time the pair had steered the score to 171 for one Ireland seemed out on their feet on a sweltering afternoon, but they rallied by claiming the next seven wickets for 77.

The pendulum had swung again thanks to a seam attack led by newcomer Mark Adair's three-for only for Sam Curran to counter with a swift 37.

Ireland's hopes of wrapping things up by stumps ended when the weather changed, leaving everything to play for on day three.

Leach had successfully negotiated his primary task on the first evening, fending off six awkward deliveries from Tim Murtagh to spare Roy and Rory Burns the trouble.

Anything else from a man with a first-class average of less than 11, a career-best of 66 and a grand total of eight from his last four innings would be seen as a bonus. Little did anyone know what the man from Taunton had up his sleeve.

If anything Burns looked like the over-promoted partner, scratching around for six before nicking Boyd Rankin behind. He has now been dismissed for 16 or fewer in nine of his 14 innings for England and heads to the Ashes in an awkward spot.

Leach opened his account with a steered four off Murtagh – the first of 16 from his bat – and was well settled by the time Roy joined him.

The World Cup winner was nervy early on but still found a way to keep things moving, with his first four scoring shots all boundaries. Only one was thoroughly convincing, two more were streaky and the other sailed off the edge through the vacant third slip region.

There was one major statement of intent as he found his feet, lashing Andy McBrine for six on the charge, and he reached his fifty in just 47 balls with an authoritative cut off Stuart Thompson.

That shot levelled the scores at lunch, with Leach responsible for chalking 60 off the target. Not only was he leaving well, he was playing straight with the full face of the bat and at one stage he hit four boundaries in seven balls.

What had started out as an amusing aside was fast becoming a major blow to the Irish cause and one of England's most accomplished opening performances since the retirement of Sir Alastair Cook.

England moved ahead for the first time in the match in the opening over of the afternoon session, Roy whipping Rankin to midwicket, but the eye was constantly drawn to Leach.

He was badly dropped on 72, Gary Wilson inexplicably allowing the ball to spill out of both gloves, and responded by going on the attack.

There was an uppish cut over backward point, a lob that evaded mid-off and a punched drive that skimmed to the ropes. One misfield at cover later and he had eclipsed the entire team's miserable day one total of 85.

England were in a handsome position when Roy had his stumps scattered by Thompson attempting an overly ambitious drive – the beginning of the Irish surge.

Leach fell eight short of becoming his country's first nightwatchman centurion, edging Murtagh to second slip, and earning a standing ovation for his efforts.

Joe Denly was run out for 10, Jonny Bairstow bagged his second duck of the game lbw to Adair and Moeen Ali came and went for nine as England crumbled.

Joe Root made a useful 32 before Adair struck again, Wilson diving in front of slip for a fine catch.

At that point England's lead was a vulnerable 117, a tally which received a vital shot in the arm from Curran, who reeled off four fours and two sixes before being held in the deep.

Woakes became Adair third scalp of the day, meaning Stuart Broad (21no) and Olly Stone were left to nudge the chase towards 200, with a frantic finish now all but certain.