AC Milan followed a 3-0 first-leg win with a 1-0 triumph to advance in the Europa League.
AC Milan confirmed their place in the Europa League's last 16 with a comfortable 1-0 victory (4-0 on aggregate) over Bulgarian side Ludogorets at the San Siro on Thursday.
Former Liverpool and Sunderland striker Fabio Borini slid in Patrick Cutrone's cross to open the scoring for the Rossoneri in the 21st minute.
In the second half, the visitors pressed for an equalizer but Swierczok wasted their best opportunity of the game when he shot straight at Donnarumma from 10 yards out.
The impressive Cutrone should have put the game to bed when Borini's shot found him at the far post, but the youngster poked his effort just wide of the goal, before Milan saw out the remaining half an hour with relative ease.
Ludogorets started the game on the front foot and nearly took the lead in the second minute with the first shot of the game. Following a good run from Swierczok on the right, the ball broke to Marcelinho 25 yards out, but the Bulgarian's subsequent effort flew over Donnarumma's goal.
After the fast start from the visitors, Milan gradually grew into the game and carved out their first opportunity in the 11th minute. A mix-up in the Ludogorets defense allowed Andre Silva to have a shot at goal from 20 yards out, but his low driven strike was too close to Broun and the keeper collected at the second attempt.
Ten minutes later and the Serie A giants opened the scoring thanks to some wonderful wing-play from their starlet Patrick. Cutrone. The youngster drove down the left side and curled his cross around the Ludogorets defense and to an unmarked Borini at the far post, who smashed the ball high into the net from four yards out.
The visitors probably should have equalized in the 27th minute when Farias' cross from the right fell to the onrushing Costa inside the Milan box, but his first-time effort fizzed well wide of the goal.
The Bulgarian champions continued to use a high press which Milan were struggling to deal with. On two separate occasions Locatelli lost the ball in a dangerous position, but the visitors were unable to take advantage and were let down by the recurring problem of poor passing in the final third.
Milan nearly doubled their lead with their first chance of the second-half in the 52nd minute. Borini cut in from the left and curled a left-footed shot towards goal from 20 yards, his effort - which was heading well wide - turned into a cross for Cutrone, but the striker could only poke the ball wide at the far post.
Five minutes later, Swierczok should have equalized for Ludogorets after Rodriguez's sliced clearance fell into his path. The striker had time and space to shoot from just 10 yards out but could only direct his effort straight at Donnarumma and the keeper punched the ball clear.
As the second-half wore on the visitors started to tire and Milan were happy to let the game peter out. Pimienta did have the chance to clinch a consolation goal when Bonucci fouled Campanharo on the edge of the box just before the end of the game, but the midfielder used too much power and his effort flew high and wide of the goal.