Armenian side Ararat-Armenia scored in the 73rd minute of their clash in Ireland to edge Shamrock Rovers 3-2 on aggregate despite a 2-1 loss on the night.
The League of Ireland pacesetters, who came into the match down 2-0 from last week's first leg, were quick to get on the board, with Matthew Healy putting them in front in the 11th minute. Later on in the opening half, Aaron Greene grabbed their second as they managed to tie the aggregate score before the interval.
Having generated the majority of the chances throughout the clash, it looked like Shamrock would have found a third to completely overturn the tie. That changed with 17 minutes left as Sandro Lima finished off an attack from close range to put Ararat-Armenia back ahead.
That goal proved to be the visitors' only attempt on target as they held on to progress to the third qualifying round. They are now assured to play league phase football this season for the very first time, becoming the fourth club from their country to go that far.
It is the sixth consecutive appearance in the Champions League for The Hoops in which they failed to make it to the third round of qualifying.
Ararat-Armenia were not the only side to secure group phase football for the first time on Tuesday. Sweden's Mjallby joined them after a 0-0 draw away to Lincoln Red Imps. Last year's Allsvenskan champions were unable to add onto their 3-0 lead from the first leg, but managed to prevail with the result in Gibraltar.
Sabah will also be making their bow in the main rounds of a UEFA club competition after a 2-0 defeat of KuPS Kuopio.
Both of the goals came in the second half in Finland, where Veljko Simic put the Azeri side in front. Joy Lance Mickels added a second on the night to send Sabah through 3-0 overall.
They are Azerbaijan's fourth different side to make a group phase after Qarabag, Neftci, and Qabala.
Dinamo Zagreb get past 10-man Thun
In Croatia, Dinamo Zagreb were once again given a proper scare against Switzerland's Thun. Purgeri pulled through in the end, scoring in the 112th minute to triumph 3-2 in extra time and 4-3 over the two legs.
Dinamo, who have reached the UCL proper on nine different occasions, found themselves 2-0 behind in the first quarter of the game, when the visitors struck through Brighton Labeau and Marco Burki. The latter soon proved to be the villain for his club, as he was given his marching orders after denying a clear goalscoring opportunity at the midpoint of the second half.
That one instant changed the game, with the hosts piling the pressure on their Swiss opponents. They found a breakthrough with 16 minutes of normal time left, when Dion Beljo found the back of the net. Moments later, Lukas Kacavenda netted a second to bring the tie back to parity.
Moris Valincic got what proved to be the winner in the second period of extra time to send the Croatians through.
Dinamo continue their impressive feat of having never been eliminated in the UCL second qualifying stage in the modern format, while Thun failed to reproduce the magic from 2005/06, where they successfully negotiated two rounds to reach the group stage.
Slovenia's Celje also struggled in their tie versus Egnatia. After a thrilling 3-3 draw in the first leg, the return match at Stadion Z'dezele was no different. Both teams led during the 120 minutes, but they once again could not be separated as penalties were required following the 2-2 draw.
The shootout saw the home side get the job done as they converted all four of their spot kicks. Egnatia, who were knocked out by Olimpija Ljubljana in the Conference League qualifiers last term, only scored once from their three attempts.
In what is their third appearance in the UCL, Celje have finally gotten past the second qualifying round, and will face Ararat-Armenia next.
Sturm Graz finished off Heart of Midlothian with a 2-0 victory at Tynecastle Park. The goals came four minutes apart for the Austrian outfit as they advance 6-0 on aggregate.
Wednesday will see the remaining eight second qualifying round ties conclude, with the likes of Fenerbahce, Crvena zvezda, and Lech Poznan all looking to close out their respective ties.
Follow the UEFA Champions League qualifying round action on Flashscore.