After securing a 1-0 lead at Bolt Arena last week, the visitors come into this match with the advantage and are the favourites to qualify for the next round, where they will take on Norwegian champions Molde.
Match preview
Larne put on a brave display in Finland last week but were notably second-best as they struggled to create many clear-cut chances and were unable to register a shot on target in three attempts in the match.
However, despite going a goal down just three minutes into the match, they played their hearts out in defence and managed to keep the scoreline at 1-0, which still leaves them with a chance at home.
While they were clinical for most of last season and in their preseason friendlies, it is worth noting that with that loss in the first leg, Larne have now failed to score in their last three competitive matches, including the final game of last season and the Charity Shield at the start of the month.
Still, it has been a tremendous journey for Tiernan Lynch's team in recent years as his side have navigated their way from the bottom of the second tier in 2017 to competing for top honours just five seasons later after winning their domestic league for the first time by a six-point margin.
They will also be able to take confidence from their excellent record at home, where they were beaten only once across the entire domestic league season, which included an unbeaten run of 10 matches between December and the end of the season.
Meanwhile, the 32-time Veikkausliiga champions set one foot in the second round with a third-minute penalty by Bojan Radulovic that turned out to be the winner in a match that they largely dominated.
However, Toni Koskela will likely feel that his side should have taken more from that match, as his attackers wasted a host of good chances with poor finishing and were caught offside far too often.
While they have been the dominant force domestically for many years, they have found it much tougher this season as they slipped to third place in the league after losing 1-0 to third-bottom FC Lahti at home the previous week.
That loss brought an end to a nine-match league unbeaten run and was also the first time that HJK Helsinky failed to score a goal since the beginning of June when they played out a stalemate against SJK.
Koskela's men suffered a disappointing end to their Europa League campaign last season, where they ended bottom of the group, and while they are noticeably some way from their best form this term, they will still be heavily fancied to progress.
Larne Champions League form:
L
Larne form (all competitions):
W
W
W
D
L
L
HJK Helsinki Champions League form:
W
HJK Helsinki form (all competitions):
W
W
D
D
L
W
Team News
Having had little effect in the first leg, Andy Ryan could make way for Newcastle United Under-21 attacker Isaac Westendorf, who came on for the final 10 minutes in the last match.
Paul O'Neill was left out of the starting lineup for Larne in the last match and could return in this one, while Daniel Kearns will be hoping to be promoted to starting 11 in place of Dylan Sloan.
Valtteri Moren and Oliver Pettersson remain the only injury absentees for HJK Helsinki, and neither are expected to return in the near future.
Radulovic got his 11th goal in all competitions in the first leg and will almost certainly retain his spot at the top of the pitch, while Roope Riski could replace Topi Keskinen in the front three.
Larne possible starting lineup:
Ferguson; Cosgrove, Want, Bolger, Donnelly; Kearns, Gordon, Glynn; Westendorf, Bonis, Millar
HJK Helsinki possible starting lineup:
Oest; Soiri, Peltola, Tenho, Raitala; Tanaka, Lingman, Hetemaj; Riski, Radulovic, Hostikka
We say: Larne 0-1 HJK Helsinki
The hosts were outplayed for the most part in the first leg, and while they should put on a better showing at home, it seems unlikely that they will be able to overturn this tie.
The visitors will prioritse keeping a clean sheet here, and if they get an early goal, we can see them sitting back and holding on to their lead to take their place in the next round.