Is OpenTal 1.1 GM standard strong?

I'm asking this because my niece, a 16-years old budding chess champion named Anne, just got beaten by OpenTal 1.1. I'm posting the game below for you to see. **1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 h6 10. d4 Re8 11. Nbd2 Bf8 12. Nf1 Bd7 13. Ng3 Na5 14. d5 Nxb3 15. axb3 a5 16. Be3 c6 17. dxc6 Bxc6 18. Qd3 Qd7 19. Red1 Qb7 20. Nd2 d5 21. f3 a4 22. b4 Rad8 23. exd5 Nxd5 24. Nde4 g6 25. Qd2 f5 26. Nc5 Qc7 27. Bf2 Nf4 28. Qc2 Qe7 29. c4 Qg5 30. cxb5 Bxb5 31. Nxa4 e4 32. Rxd8 Qxd8 33. fxe4 fxe4 34. Nxe4 Bd3 35. Qb3+ Kh8 36. Bb6 Qe7 37. Bd4+ Bg7 38. Bxg7+ Kxg7 39. Qc3+ Kf7 40. Qb3+ Kf8 41. Nac5 Bxe4 42. Rf1 g5 43. Qc3 Bf5 44. Kh1 Qe2 45. Rg1 Kf7 46. b3 Kg6 47. Qc4 Qf2 48. Qf1 Qg3 49. Qf3 Qxf3 50. gxf3 Bxh3 51. Ra1 Bg2+ 52. Kg1 Re2 53. Ra6+ Kh5 54. Ne6 Nxe6 55. Rxe6 Rxe6 56. Kxg2 Rb6 57. b5 Rxb5 58. Kf2 Rxb3 59. Kg3 g4 60. Kf2 gxf3 0-1** Anne is a brilliant chess player, a FIDE accredited titleholder and a miniature star in our local chess community. Yesterday she came to our home and played OpenTal 1.1 running on a 5-year old Moto G5 Plus, an android device of my daughter. She became so dedicated to the game that she played through just under four hours, sixty moves before she resigned. Later, she told my daughter, also a chess enthusiast, that she had resigned because "my case was hopeless, despite my best efforts OpenTal was too good for me". She did struggle against the engine, at times (especially during the latter half of the game) it was harrowing to see her, thinking her brains out, sweating profusely despite the weather being pleasant and swearing under her breath. I was kind of relieved when she finally had the good sense to resign. I consoled her, saying that it is no good playing chess engines. Even the best human player cannot hope to beat the top engines. Yet this game made me curious. How strong is OpenTal, considering it was running on pretty basic android hardware system? And how did Anne fared against it? I'll subject this to Stockfish analysis, of course, but that wouldn't tell me the strength of the engine and the quality of Anne's defence. If you could contribute your knowledge to illuminate me, it would be a chess help. Pardon me for any linguistic errors, as English is the third language I learnt, and I'm not much fluent in it. (Similar query is also posted in other chess forums - Andreya)

The guys in the know estimate it's about 2500 to 2600 Elo. I'm assuming that would be on standard desktop equipment. I'm sure it's considerably lower on an Android, but I have no idea how much weaker.