There were seven Lions on display at the RDS - Rob Kearney, Johnny Sexton, man of the match Sean O'Brien, Adam Jones, Alun Wyn Jones and Justin Tipuric - but Brian O'Driscoll and Ian Evans stayed on the bench for their respective teams.
Maitland's try for Glasgow made their victory secure in Galway as they beat Connacht 20-3 to finish third overall. The wing raced clear to score in the corner with 10 minutes left to play.
Glasgow's other Lion, Stuart Hogg, added the conversion to a penalty he kicked just before the try and the Scottish full back looked very much at home fitting in at outside half for his club. Both men will now face Leinster in Dublin next weekend.
The other Play-Off game next weekend will see Ulster Rugby host the Scarlets at Ravenhill - a game that could see Tommy Bowe go up against George North. Ulster came from behind to beat Cardiff Blues 37-13 top finsih the regular season at the top of the table, while the Scarlets were stunned at home against Benetton Treviso as they went down to a 41-17 defeat.
None of the Blues' four Lions played in the game, while Bowe played for 69 minutes. North and Jonathan Davies started for the Scarlets, with North leaving the fray just before the end.
The outcome of the matches in Round 22 means that only 11 of the RaboDirect PRO12's 24 British & Irish Lions will be required for club duty in the Play-Off games next weekend. Leinster then meet Stade Francais Paris in the final of the Amlin Challenge Cup in Dublin on Friday, 17 May, before the last act of the domestic season takes place on Saturday, 25 May, with the RaboDirect PRO12 final.
The Aviva Premiership clubs all play today.