Daniel Ricciardo went quickest for the second session in a row, edging team-mate Max Verstappen by almost two tenths of a second in a practice period interrupted by red flags shown to allow for track repairs.
Verstappen set the pace early on with a hypersoft tyre time of 1:12.468s as the session neared the 20-minute mark. He improved to a time of 1:12.071s before the red flags were shown after 25 minutes.
Workmen were sent on track to weld into place what appeared to be a loose drain and after a 15-minute delay the action resumed again with Verstappen again finding more time with a lap of 1:12.035.
Ricciardo left his qualifying simulation late, but when he eventually emerged a little under 20 minutes from the end of the session he found enough space on what had been a crowded track to become the only man under the 1m12s barrier and his laps of 1:11.841s vaulted him to the top of the order.
Sebastian Vettel was third fastest for Ferrari, 0.378s off the pace and just over a tenth ahead of Mercedes Lewis Hamilton, who edged Vettel’s team-mate Kimi Räikkönen by just nine thousandths of a second. Hamilton’s team-mate Valtteri Bottas was sixth, 0.099s slower than fellow Finn Räikkönen.
Renault's Nico Hulkenberg was seventh ahead of McLaren’s Stoffel Vandoorne and team-mate Fernando Alonso, who enjoyed a much more fruitful session than in the morning, when they finished 15th and 17th respectively.
Tenth place in the session was taken by Carlos Sainz in the second Renault, with the Spaniard finishing 1.398s off the pace. Sainz was marginally ahead of Toro Rosso’s Brendon Hartley who brushed with the wall with his right rear in the latter stages of the 90 minutes.
2018 Formula 1 Monaco Grand Prix – Free Practice 2
1 Daniel Ricciardo Red Bull Racing 33 1:11.841
2 Max Verstappen Red Bull Racing 41 1:12.035 0.194
3 Sebastian Vettel Ferrari 42 1:12.413 0.572
4 Lewis Hamilton Mercedes 34 1:12.536 0.695
5 Kimi Raikkonen Ferrari 36 1:12.543 0.702
6 Valtteri Bottas Mercedes 38 1:12.642 0.801
7 Nico Hulkenberg Renault 30 1:13.047 1.206
8 Stoffel Vandoorne McLaren 40 1:13.077 1.236
9 Fernando Alonso McLaren 42 1:13.115 1.274
10 Carlos Sainz Renault 34 1:13.200 1.359
11 Brendon Hartley Toro Rosso 47 1:13.222 1.381
12 Sergio Perez Force India 39 1:13.370 1.529
13 Esteban Ocon Force India 47 1:13.38 1.541
14 Pierre Gasly Toro Rosso 32 1:13.410 1.569
15 Sergey Sirotkin Williams 44 1:13.547 1.706
16 Kevin Magnussen Haas 41 1:13.572 1.731
17 Charles Leclerc Sauber 45 1:13.575 1.734
18 Romain Grosjean Haas 37 1:13.763 1.922
19 Lance Stroll Williams 34 1:14.011 2.170
20 Marcus Ericsson Sauber 46 1:14.173 2.332