April 25 (Reuters) - Industrial parts provider W.W. Grainger reported a 3.4% increase in first-quarter revenue on Thursday, helped by demand from its U.S. industrial clients for maintenance and repair equipment.

The Illinois-based company, which sells safety, maintenance, and repair equipment to North American, Japanese industrial clients, and domestic consumers, reported a quarterly profit of $9.65 per share, a slight increase from per-share earnings of $9.61 a year ago.

Daily sales at the company's High-Touch Solutions segment, which caters to the North American manufacturing, warehousing, and metalworking industries, were up 3.4% year-over-year.

The unfavorable product mix in Zoro, a subsidiary of W.W. Grainger, weighed on its online-only "Endless Assortment" segment's gross profit margin, which declined 0.3%. Total quarterly revenue was at $4.23 billion.

(Reporting by Pratyush Thakur in Bengaluru; Editing by Ravi Prakash Kumar)