How it happened
Mads Borchers scored a hat-trick as HJK beat IF Gnistan 4-0 at Bolt Arena, and all four goals came after a goalless first half.
Borchers broke the deadlock in the 50th minute. Three minutes later Gnistan were reduced to 10 men when Arko-Mensah was sent off. Haarala doubled the lead in the 60th minute, and Borchers made it three in the 66th.
Gnistan held out for a long spell after that, but Borchers completed his hat-trick with a goal in added time at the end of the match.
The numbers
HJK had 19 shots to Gnistan's 10, with 10 on target against four. They held 69% of possession and finished on 3.37 expected goals to 0.43, an estimated figure that reflects the scale of their control. Gnistan did win more corners, six to four.
Borchers took a match rating of 10 for his three goals, and he also made three key passes in 50 touches. At the other end, Virtanen kept the score down with six saves and a match rating of 7.8. HJK's Jesse Öst made four saves and was rated 7.7.
What it means
The table has HJK second with 51 points from 28 games and Gnistan fourth with 42, a gap of nine points. HJK arrived with a sequence of win, win, draw, draw, win. Gnistan's was defeat, draw, draw, win, draw.
The result extends HJK's edge in the head-to-head record to seven wins from 12 meetings, against three for Gnistan and two draws. Their previous two meetings, however, had gone to Gnistan, 3-2, and ended 1-1, so this was a sharper statement than recent history suggested.