Singles
2021 Biella Challenger Indoor II
Final
Champion	Kwon Soon-woo
Runner-up	Lorenzo Musetti
Score	6–2, 6–3
Events
Singles Doubles
← 2021 · Biella Challenger Indoor · 2021 →

This was the second of seven editions of the tournament in the 2021 tennis season.^[1] Illya Marchenko was the defending champion but lost in the quarterfinals to Andreas Seppi.

Kwon Soon-woo won the title after defeating Lorenzo Musetti 6–2, 6–3 in the final.

	Semifinals							Final
	8	Evgeny Donskoy	3	77	1
	3	Kwon Soon-woo	6	64	6
								3	Kwon Soon-woo	6	6
								7	Lorenzo Musetti	2	3
	4	Andreas Seppi	6	3	4
	7	Lorenzo Musetti	3	6	6

	First round							Second round							Quarterfinals							Semifinals
	1	A Davidovich Fokina	6	6
		S Diez	3	0				1	A Davidovich Fokina	62	4
		F Gaio	6	6					F Gaio	77	6
	LL	H Moriya	3	1												F Gaio	3	2
	Q	C Lestienne	5	712	77										8	E Donskoy	6	6
	WC	L Nardi	7	610	60			Q	C Lestienne	4	2
		M Safwat	3	4				8	E Donskoy	6	6
	8	E Donskoy	6	6																		8	E Donskoy	3	77	1
	3	S-w Kwon	6	6																		3	S-w Kwon	6	64	6
		J Jung	3	4				3	S-w Kwon	6	6
		R Marcora	77	6					R Marcora	2	2
		H Laaksonen	64	1											3	S-w Kwon	6	6
		A Giannessi	1	4												Y Maden	2	1
		T Fabbiano	6	6					T Fabbiano	63	1
		Y Maden	6	6					Y Maden	77	6
	6	A Hoang	0	2

	First round							Second round							Quarterfinals							Semifinals
	5	K Majchrzak	77	6
		B Rola	65	4				5	K Majchrzak	6	4	1
	SE	I Marchenko	77	4	6			SE	I Marchenko	1	6	6
	WC	G Zeppieri	61	6	3										SE	I Marchenko	4	5
		B Zapata Miralles	65	4											4	A Seppi	6	7
		M Kližan	77	6					M Kližan	68	3
	Q	M Viola	2	6	5			4	A Seppi	710	6
	4	A Seppi	6	4	7																	4	A Seppi	6	3	4
	7	L Musetti	7	6																		7	L Musetti	3	6	6
	WC	S Napolitano	5	3				7	L Musetti	6	6
	Q	B Kavčič	3	2				Alt	L Lacko	4	3
	Alt	L Lacko	6	6											7	L Musetti	6	6
	Q	R Brancaccio	6	3	4										Alt	E Gulbis	2	4
	Alt	E Gulbis	4	6	6			Alt	E Gulbis	6	6
		D Popko	6	6					D Popko	1	4
	2	S Korda	4	3

• Main draw
• Qualifying draw