Ireland fought back during the second half of day four of their first ever Test match after a career-defining century from Kevin O'Brien rescued the hosts from the brink.

The red-haired veteran put on 114 runs with Stuart Thompson to not only make Pakistan bat again but also throw open a wealth of possibilities on the final day at Malahide. The home side recovered from 157/6 to end day four on 319/7, with a lead of 139 runs and three wickets remaining. 

This Test saw Ireland launch an exciting new chapter as they became the first team to debut in Test cricket since Bangladesh in 2000, having been awarded full member status by the ICC last summer, along with Afghanistan. Today, Ireland proved they're up to the task. 

Earlier in the match, Pakistan declared on 310/9 before bundling out Ireland for 130 and enforcing a follow-on for the first time since 2002. Day three had seen Irish stalwarts Ed Joyce and skipper William Porterfield carry their team unbeaten at 64-0 at the close, although a deficit of 116 runs remained; the Test debutants were unable to take that momentum into day four. 

Pakistan had been rocked by the sight of Mohammad Amir hobbling off the field with a knee injury two balls into his fourth over yesterday, but Ireland’s respite from Pakistan’s leader of the attack proved short-lived. The left-armer bowled with real potency during the morning session, claiming the wickets of Porterfield who was caught behind for 32 courtesy of a brilliant grab by Sarfraz Ahmed, and Niall O'Brien, who saw his off and middle stump flying out of the ground – a tremendous sight for any speedster.

However, Ed Joyce (43) was the first to depart, run out by Faheem Ashraf, before Andrew Balbirnie fell lbw to Mohammad Abbas for the second time in the match. It was Balbirnie's second duck in the game, although he may find comfort in learning that Graham Gooch, Saeed Anwar, Marvin Attapattu and Dean Elgar have all flopped with a pair on their first Test outing. 

Amir bowled beautifully – he was all over Porterfield at one point – but it was clear that he was still suffering. With Pakistan's next Test in 10 days, and this one, at the time, all but won, it was surprising that they weren’t protecting him a little more. Ireland's late-innings revival, however, would soon prove it was a risk worth taking. 

Abbas removed Paul Stirling (11) with an lbw shout shortly after lunch after umpire Nigel Llong had adjudged that the ball had brushed the pad before making contact with Stirling's blade. It was a tight call, but after the benefit of several replays it felt like a fair decision.

Abbas was now getting a lot of seam movement, as Ireland tried to dig in, while leg-spinner Shadab Khan was also extracting some good turn. Amir returned to dismiss Gary Wilson, caught at second slip, and claimed his 100th Test wicket in the process.

Then, just when it had looked like damage limitation from the home side, Kevin O'Brien and Thompson began to rebuild confidence, ushering Ireland into a competitive position throughout the latter part of the second session and into the third. Ireland weren't going down without a fight. 

Kevin O'Brien became the first Irish batsman to reach fifty in men's Test cricket, soaking up the pressure, fighting his natural game and using every ounce of experience, and the duo's fifty partnership was brought up just before tea. Thompson nailed a pull shot through midwicket to bring up his fifty after the break as Irish fans dared to dream. The pair had well and truly seen off the second new ball.

Thompson, the No.8, eventually fell for 53, owed to a ripping legbreak from Shadab, which span out of the rough and into the stumps, bringing an end to a gutsy 114-run partnership. O'Brien remained, edging ever closer to becoming Ireland's first ever Test match century-maker. 

After getting through the nervous nineties for what must have seemed like an eternity for the Ireland fans, O'Brien etched himself into the record books with a memorable innings that summed up the character and grit of Test cricket's newbies. The entire crowd rose to applaud a beaming O'Brien – the chief catalyst of an unlikely comeback. 

Half-way through day four, Ireland looked like they had been outclassed by an experienced Test side, although they had by no means been passengers. Initiations are never easy, after all; Australia remain the only side to have won their inaugural Test, beating England in Melbourne in 1877.

However, by stumps, Ireland's fighting spirit had booked an interesting final day on Tuesday where all results are now possible. It's only what this historical cricket match deserved.